Merge pull request 'feat: systemd auto-start for ROS2 + dashboard on Orin boot (bd-1hyn)' (#732) from sl-perception/bd-1hyn-orin-autostart into main

Extends the bd-66hx serial protocol with two new Orin→ESP32 commands:
  CMD_OTA_CHECK  (0x10): triggers gitea_ota_check_now(), responds with
    TELEM_VERSION_INFO (0x84) for Balance and IO (current + available ver).
  CMD_OTA_UPDATE (0x11): uint8 target (0=balance, 1=io, 2=both) — triggers
    uart_ota_trigger() for IO or ota_self_trigger() for Balance.
    NACK with ERR_OTA_BUSY or ERR_OTA_NO_UPDATE on failure.
New telemetry: TELEM_OTA_STATUS (0x83, target+state+progress+err),
  TELEM_VERSION_INFO (0x84, target+current[16]+available[16]).
Wires OTA stack into app_main: ota_self_health_check on boot,
  gitea_ota_init + ota_display_init after peripherals ready.
CMakeLists updated with all OTA component dependencies.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

.gitea/workflows/ota-release.yml

@@ -0,0 +1,162 @@
+# .gitea/workflows/ota-release.yml
+# Gitea Actions — ESP32 OTA firmware build & release (bd-9kod)
+#
+# Triggers on signed release tags:
+#   esp32-balance/vX.Y.Z  →  builds esp32s3/balance/   (ESP32-S3 Balance board)
+#   esp32-io/vX.Y.Z       →  builds esp32s3-io/         (ESP32-S3 IO board)
+#
+# Uses the official espressif/idf Docker image for reproducible builds.
+# Attaches <app>_<version>.bin + <app>_<version>.sha256 to the Gitea release.
+# The ESP32 Balance OTA system fetches the .bin from the release asset URL.
+
+name: OTA release — build & attach firmware
+
+on:
+  push:
+    tags:
+      - "esp32-balance/v*"
+      - "esp32-io/v*"
+
+permissions:
+  contents: write
+
+jobs:
+  build-and-release:
+    name: Build ${{ github.ref_name }}
+    runs-on: ubuntu-latest
+    container:
+      image: espressif/idf:v5.2.2
+      options: --user root
+
+    steps:
+      # ── 1. Checkout ───────────────────────────────────────────────────────────
+      - name: Checkout
+        uses: actions/checkout@v4
+
+      # ── 2. Resolve build target from tag ─────────────────────────────────────
+      # Tag format:  esp32-balance/v1.2.3  or  esp32-io/v1.2.3
+      - name: Resolve project from tag
+        id: proj
+        shell: bash
+        run: |
+          TAG="${GITHUB_REF_NAME}"
+          case "$TAG" in
+            esp32-balance/*)
+              DIR="esp32s3/balance"
+              APP="esp32s3_balance"
+              ;;
+            esp32-io/*)
+              DIR="esp32s3-io"
+              APP="esp32s3_io"
+              ;;
+            *)
+              echo "::error::Unrecognised tag prefix: ${TAG}"
+              exit 1
+              ;;
+          esac
+          VERSION="${TAG#*/}"
+          echo "dir=${DIR}"         >> "$GITHUB_OUTPUT"
+          echo "app=${APP}"         >> "$GITHUB_OUTPUT"
+          echo "version=${VERSION}" >> "$GITHUB_OUTPUT"
+          echo "tag=${TAG}"         >> "$GITHUB_OUTPUT"
+          echo "Build: ${APP} ${VERSION} from ${DIR}"
+
+      # ── 3. Build with ESP-IDF ─────────────────────────────────────────────────
+      - name: Build firmware (idf.py build)
+        shell: bash
+        run: |
+          . "${IDF_PATH}/export.sh"
+          cd "${{ steps.proj.outputs.dir }}"
+          idf.py build
+
+      # ── 4. Collect binary & generate checksum ────────────────────────────────
+      - name: Collect artifacts
+        id: art
+        shell: bash
+        run: |
+          APP="${{ steps.proj.outputs.app }}"
+          VER="${{ steps.proj.outputs.version }}"
+          BIN_SRC="${{ steps.proj.outputs.dir }}/build/${APP}.bin"
+          BIN_OUT="${APP}_${VER}.bin"
+          SHA_OUT="${APP}_${VER}.sha256"
+
+          cp "$BIN_SRC" "$BIN_OUT"
+          sha256sum "$BIN_OUT" > "$SHA_OUT"
+
+          echo "bin=${BIN_OUT}" >> "$GITHUB_OUTPUT"
+          echo "sha=${SHA_OUT}" >> "$GITHUB_OUTPUT"
+
+          echo "Binary:   ${BIN_OUT} ($(wc -c < "$BIN_OUT") bytes)"
+          echo "Checksum: $(cat "$SHA_OUT")"
+
+      # ── 5. Archive artifacts in CI workspace ─────────────────────────────────
+      - name: Upload build artifacts
+        uses: actions/upload-artifact@v4
+        with:
+          name: firmware-${{ steps.proj.outputs.app }}-${{ steps.proj.outputs.version }}
+          path: |
+            ${{ steps.art.outputs.bin }}
+            ${{ steps.art.outputs.sha }}
+
+      # ── 6. Create Gitea release (if needed) & upload assets ──────────────────
+      # Uses GITHUB_TOKEN (auto-provided, contents:write from permissions block).
+      # URL-encodes the tag to handle the slash in esp32-balance/vX.Y.Z.
+      - name: Publish assets to Gitea release
+        shell: bash
+        env:
+          GITEA_URL: https://gitea.vayrette.com
+          TOKEN: ${{ secrets.GITHUB_TOKEN }}
+          REPO: ${{ github.repository }}
+          TAG: ${{ steps.proj.outputs.tag }}
+          BIN: ${{ steps.art.outputs.bin }}
+          SHA: ${{ steps.art.outputs.sha }}
+        run: |
+          API="${GITEA_URL}/api/v1/repos/${REPO}"
+
+          # URL-encode the tag (slash in esp32-balance/vX.Y.Z must be escaped)
+          TAG_ENC=$(python3 -c "
+          import urllib.parse, sys
+          print(urllib.parse.quote(sys.argv[1], safe=''))
+          " "$TAG")
+
+          # Try to fetch an existing release for this tag
+          RELEASE=$(curl -sf \
+            -H "Authorization: token ${TOKEN}" \
+            "${API}/releases/tags/${TAG_ENC}") || true
+
+          # If no release yet, create it
+          if [ -z "$RELEASE" ]; then
+            echo "Creating release for tag: ${TAG}"
+            RELEASE=$(curl -sf \
+              -X POST \
+              -H "Authorization: token ${TOKEN}" \
+              -H "Content-Type: application/json" \
+              -d "$(python3 -c "
+          import json, sys
+          print(json.dumps({
+              'tag_name': sys.argv[1],
+              'name':     sys.argv[1],
+              'draft':    False,
+              'prerelease': False,
+          }))
+          " "$TAG")" \
+              "${API}/releases")
+          fi
+
+          RELEASE_ID=$(echo "$RELEASE" | python3 -c "
+          import sys, json; print(json.load(sys.stdin)['id'])
+          ")
+          echo "Release ID: ${RELEASE_ID}"
+
+          # Upload binary and checksum
+          for FILE in "$BIN" "$SHA"; do
+            FNAME=$(basename "$FILE")
+            echo "Uploading: ${FNAME}"
+            curl -sf \
+              -X POST \
+              -H "Authorization: token ${TOKEN}" \
+              -F "attachment=@${FILE}" \
+              "${API}/releases/${RELEASE_ID}/assets?name=${FNAME}"
+          done
+
+          echo "Published: ${BIN} + ${SHA} → release ${TAG}"

.pio/build/project.checksum

@@ -1 +1 @@
-8700a44a6597bcade0f371945c539630ba0e78b1
+ffc01fb580c81760bdda9a672fe1212be4578e3e

AUTONOMOUS_ARMING.md

@@ -7,7 +7,11 @@ The robot can now be armed and operated autonomously from the Jetson without req
 
 ### Jetson Autonomous Arming
 - Command: `A\n` (single byte 'A' followed by newline)
-- Sent via USB CDC to the STM32 firmware
+<<<<<<< HEAD
+- Sent via USB CDC to the ESP32 BALANCE firmware
+=======
+- Sent via USB Serial (CH343) to the ESP32-S3 firmware
+>>>>>>> 291dd68 (feat: remove all STM32/Mamba/BlackPill references — ESP32-S3 only)
 - Robot arms after ARMING_HOLD_MS (~500ms) safety hold period
 - Works even when RC is not connected or not armed
 
@@ -42,7 +46,11 @@ The robot can now be armed and operated autonomously from the Jetson without req
 
 ## Command Protocol
 
-### From Jetson to STM32 (USB CDC)
+<<<<<<< HEAD
+### From Jetson to ESP32 BALANCE (USB CDC)
+=======
+### From Jetson to ESP32-S3 (USB Serial (CH343))
+>>>>>>> 291dd68 (feat: remove all STM32/Mamba/BlackPill references — ESP32-S3 only)
 ```
 A           — Request arm (triggers safety hold, then motors enable)
 D           — Request disarm (immediate motor stop)
@@ -52,7 +60,11 @@ H           — Heartbeat (refresh timeout timer, every 500ms)
 C<spd>,<str> — Drive command: speed, steer (also refreshes heartbeat)
 ```
 
-### From STM32 to Jetson (USB CDC)
+<<<<<<< HEAD
+### From ESP32 BALANCE to Jetson (USB CDC)
+=======
+### From ESP32-S3 to Jetson (USB Serial (CH343))
+>>>>>>> 291dd68 (feat: remove all STM32/Mamba/BlackPill references — ESP32-S3 only)
 Motor commands are gated by `bal.state == BALANCE_ARMED`:
 - When ARMED: Motor commands sent every 20ms (50 Hz)
 - When DISARMED: Zero sent every 20ms (prevents ESC timeout)

CLAUDE.md

@@ -1,17 +1,36 @@
 # SaltyLab Firmware — Agent Playbook
 
 ## Project
-Self-balancing two-wheeled robot: STM32F722 flight controller, hoverboard hub motors, Jetson Nano for AI/SLAM.
+<<<<<<< HEAD
+**SAUL-TEE** — 4-wheel wagon (870×510×550 mm, 23 kg).
+Two ESP32-S3 boards + Jetson Orin via CAN. Full spec: `docs/SAUL-TEE-SYSTEM-REFERENCE.md`
+
+| Board | Role |
+|-------|------|
+| **ESP32-S3 BALANCE** | QMI8658 IMU, PID balance, CAN→VESC (L:68 / R:56), GC9A01 LCD (Waveshare Touch LCD 1.28) |
+| **ESP32-S3 IO** | TBS Crossfire RC, ELRS failover, BTS7960 motors, NFC/baro/ToF, WS2812 |
+| **Jetson Orin** | AI/SLAM, CANable2 USB→CAN, cmds 0x300–0x303, telemetry 0x400–0x401 |
+
+> **Legacy:** `src/` and `include/` = archived STM32 HAL — do not extend. New firmware in `esp32/`.
+=======
+Self-balancing two-wheeled robot: ESP32-S3 ESP32-S3 BALANCE, hoverboard hub motors, Jetson Orin Nano Super for AI/SLAM.
+>>>>>>> 291dd68 (feat: remove all STM32/Mamba/BlackPill references — ESP32-S3 only)
 
 ## Team
 | Agent | Role | Focus |
 |-------|------|-------|
-| **sl-firmware** | Embedded Firmware Lead | STM32 HAL, USB CDC debugging, SPI/UART, PlatformIO, DFU bootloader |
+<<<<<<< HEAD
+| **sl-firmware** | Embedded Firmware Lead | ESP32-S3, ESP-IDF, QMI8658, CAN/UART protocol, BTS7960 |
+| **sl-controls** | Control Systems Engineer | PID tuning, IMU fusion, balance loop, safety |
+| **sl-perception** | Perception / SLAM Engineer | Jetson Orin, RealSense D435i, RPLIDAR, ROS2, Nav2 |
+=======
+| **sl-firmware** | Embedded Firmware Lead | ESP-IDF, USB Serial (CH343) debugging, SPI/UART, PlatformIO, DFU bootloader |
 | **sl-controls** | Control Systems Engineer | PID tuning, IMU sensor fusion, real-time control loops, safety systems |
-| **sl-perception** | Perception / SLAM Engineer | Jetson Nano, RealSense D435i, RPLIDAR, ROS2, Nav2 |
+| **sl-perception** | Perception / SLAM Engineer | Jetson Orin Nano Super, RealSense D435i, RPLIDAR, ROS2, Nav2 |
+>>>>>>> 291dd68 (feat: remove all STM32/Mamba/BlackPill references — ESP32-S3 only)
 
 ## Status
-USB CDC TX bug resolved (PR #10 — DCache MPU non-cacheable region + IWDG ordering fix).
+USB Serial (CH343) TX bug resolved (PR #10 — DCache MPU non-cacheable region + IWDG ordering fix).
 
 ## Repo Structure
 - `projects/saltybot/SALTYLAB.md` — Design doc
@@ -29,11 +48,11 @@ USB CDC TX bug resolved (PR #10 — DCache MPU non-cacheable region + IWDG order
 | `saltyrover-dev` | Integration — rover variant |
 | `saltytank` | Stable — tracked tank variant |
 | `saltytank-dev` | Integration — tank variant |
-| `main` | Shared code only (IMU drivers, USB CDC, balance core, safety) |
+| `main` | Shared code only (IMU drivers, USB Serial (CH343), balance core, safety) |
 
 ### Rules
 - Agents branch FROM `<variant>-dev` and PR back TO `<variant>-dev`
-- Shared/infrastructure code (IMU drivers, USB CDC, balance core, safety) goes in `main`
+- Shared/infrastructure code (IMU drivers, USB Serial (CH343), balance core, safety) goes in `main`
 - Variant-specific code (motor topology, kinematics, config) goes in variant branches
 - Stable branches get promoted from `-dev` after review and hardware testing
 - **Current SaltyLab team** works against `saltylab-dev`

TEAM.md

@@ -1,12 +1,22 @@
 # SaltyLab — Ideal Team
 
 ## Project
-Self-balancing two-wheeled robot using a drone flight controller (STM32F722), hoverboard hub motors, and eventually a Jetson Nano for AI/SLAM.
+<<<<<<< HEAD
+**SAUL-TEE** — 4-wheel wagon (870×510×550 mm, 23 kg).
+Two ESP32-S3 boards (BALANCE + IO) + Jetson Orin. See `docs/SAUL-TEE-SYSTEM-REFERENCE.md`.
+
+## Current Status
+- **Hardware:** ESP32-S3 BALANCE (Waveshare Touch LCD 1.28, CH343 USB) + ESP32-S3 IO (bare devkit, JTAG USB)
+- **Firmware:** ESP-IDF/PlatformIO target; legacy `src/` STM32 HAL archived
+- **Comms:** UART 460800 baud inter-board; CANable2 USB→CAN for Orin; CAN 500 kbps to VESCs (L:68 / R:56)
+=======
+Self-balancing two-wheeled robot using a drone ESP32-S3 BALANCE (ESP32-S3), hoverboard hub motors, and eventually a Jetson Orin Nano Super for AI/SLAM.
 
 ## Current Status
 - **Hardware:** Assembled — FC, motors, ESC, IMU, battery, RC all on hand
-- **Firmware:** Balance PID + hoverboard ESC protocol written, but blocked by USB CDC bug
-- **Blocker:** USB CDC TX stops working when peripheral inits (SPI/UART/GPIO) are added alongside USB OTG FS — see `USB_CDC_BUG.md`
+- **Firmware:** Balance PID + hoverboard ESC protocol written, but blocked by USB Serial (CH343) bug
+- **Blocker:** USB Serial (CH343) TX stops working when peripheral inits (SPI/UART/GPIO) are added alongside USB on ESP32-S3 — see `legacy/stm32/USB_CDC_BUG.md` for historical context
+>>>>>>> 291dd68 (feat: remove all STM32/Mamba/BlackPill references — ESP32-S3 only)
 
 ---
 
@@ -14,18 +24,30 @@ Self-balancing two-wheeled robot using a drone flight controller (STM32F722), ho
 
 ### 1. Embedded Firmware Engineer (Lead)
 **Must-have:**
-- Deep STM32 HAL experience (F7 series specifically)
+<<<<<<< HEAD
+- Deep ESP32 (Arduino/ESP-IDF) or STM32 HAL experience
 - USB OTG FS / CDC ACM debugging (TxState, endpoint management, DMA conflicts)
-- SPI + UART + USB coexistence on STM32
-- PlatformIO or bare-metal STM32 toolchain
+- SPI + UART + USB coexistence on ESP32
+- PlatformIO or bare-metal ESP32 toolchain
 - DFU bootloader implementation
+=======
+- Deep ESP-IDF experience (ESP32-S3 specifically)
+- USB Serial (CH343) / UART debugging on ESP32-S3
+- SPI + UART + USB coexistence on ESP32-S3
+- ESP-IDF / Arduino-ESP32 toolchain
+- OTA firmware update implementation
+>>>>>>> 291dd68 (feat: remove all STM32/Mamba/BlackPill references — ESP32-S3 only)
 
 **Nice-to-have:**
-- Betaflight/iNav/ArduPilot codebase familiarity
+- ESP32-S3 peripheral coexistence (SPI + UART + USB)
 - PID control loop tuning for balance robots
 - FOC motor control (hoverboard ESC protocol)
 
-**Why:** The immediate blocker is a USB peripheral conflict. Need someone who's debugged STM32 USB issues before — this is not a software logic bug, it's a hardware peripheral interaction issue.
+<<<<<<< HEAD
+**Why:** The immediate blocker is a USB peripheral conflict. Need someone who's debugged STM32 USB issues before — ESP32 firmware for the balance loop and I/O needs to be written from scratch.
+=======
+**Why:** The immediate blocker is a USB peripheral conflict on ESP32-S3. Need someone who's debugged ESP32-S3 USB Serial (CH343) issues before — this is not a software logic bug, it's a hardware peripheral interaction issue.
+>>>>>>> 291dd68 (feat: remove all STM32/Mamba/BlackPill references — ESP32-S3 only)
 
 ### 2. Control Systems / Robotics Engineer
 **Must-have:**
@@ -43,7 +65,7 @@ Self-balancing two-wheeled robot using a drone flight controller (STM32F722), ho
 
 ### 3. Perception / SLAM Engineer (Phase 2)
 **Must-have:**
-- Jetson Nano / NVIDIA Jetson platform
+- Jetson Orin Nano Super / NVIDIA Jetson platform
 - Intel RealSense D435i depth camera
 - RPLIDAR integration
 - SLAM (ORB-SLAM3, RTAB-Map, or similar)
@@ -54,19 +76,23 @@ Self-balancing two-wheeled robot using a drone flight controller (STM32F722), ho
 - Obstacle avoidance
 - Nav2 stack
 
-**Why:** Phase 2 goal is autonomous navigation. Jetson Nano with RealSense + RPLIDAR for indoor mapping and person following.
+**Why:** Phase 2 goal is autonomous navigation. Jetson Orin Nano Super with RealSense + RPLIDAR for indoor mapping and person following.
 
 ---
 
 ## Hardware Reference
 | Component | Details |
 |-----------|---------|
-| FC | MAMBA F722S (STM32F722RET6, MPU6000) |
+<<<<<<< HEAD
+| FC | ESP32 BALANCE (ESP32RET6, MPU6000) |
+=======
+| FC | ESP32-S3 BALANCE (ESP32-S3RET6, QMI8658) |
+>>>>>>> 291dd68 (feat: remove all STM32/Mamba/BlackPill references — ESP32-S3 only)
 | Motors | 2x 8" pneumatic hoverboard hub motors |
 | ESC | Hoverboard ESC (EFeru FOC firmware) |
 | Battery | 36V pack |
 | RC | BetaFPV ELRS 2.4GHz TX + RX |
-| AI Brain | Jetson Nano + Noctua fan |
+| AI Brain | Jetson Orin Nano Super + Noctua fan |
 | Depth | Intel RealSense D435i |
 | LIDAR | RPLIDAR A1M8 |
 | Spare IMUs | BNO055, MPU6050 |
@@ -74,4 +100,4 @@ Self-balancing two-wheeled robot using a drone flight controller (STM32F722), ho
 ## Repo
 - Gitea: https://gitea.vayrette.com/seb/saltylab-firmware
 - Design doc: `projects/saltybot/SALTYLAB.md`
-- Bug doc: `USB_CDC_BUG.md`
+- Bug doc: `legacy/stm32/USB_CDC_BUG.md` (archived — STM32 era)

USB_CDC_BUG.md

@@ -1,44 +0,0 @@
-# USB CDC TX Bug — 2026-02-28
-
-## Problem
-Balance firmware produces no USB CDC output. Minimal "hello" test firmware works fine.
-
-## What Works
-- **Test firmware** (just sends `{"hello":N}` at 10Hz after 3s delay): **DATA FLOWS**
-- USB enumeration works in both cases (port appears as `/dev/cu.usbmodemSALTY0011`)
-- DFU reboot via RTC backup register works (Betaflight-proven pattern)
-
-## What Doesn't Work
-- **Balance firmware**: port opens, no data ever arrives
-- Tried: removing init transmit, 3s boot delay, TxState recovery, DTR detection, streaming flags
-- None of it helps
-
-## Key Difference Between Working & Broken
-- **Working test**: main.c only includes USB CDC headers, HAL, string, stdio
-- **Balance firmware**: includes icm42688.h, bmp280.h, balance.h, hoverboard.h, config.h, status.h
-- Balance firmware inits SPI1 (IMU), USART2 (hoverboard), GPIO (LEDs, buzzer)
-- Likely culprit: **peripheral init (SPI/UART/GPIO) is interfering with USB OTG FS**
-
-## Suspected Root Cause
-One of the additional peripheral inits (SPI1 for IMU, USART2 for hoverboard ESC, or GPIO for status LEDs) is likely conflicting with the USB OTG FS peripheral — either a clock conflict, GPIO pin conflict, or interrupt priority issue.
-
-## Hardware
-- MAMBA F722S FC (STM32F722RET6)
-- Betaflight target: DIAT-MAMBAF722_2022B
-- IMU: MPU6000 on SPI1 (PA4/PA5/PA6/PA7)
-- USB: OTG FS (PA11/PA12)
-- Hoverboard ESC: USART2 (PA2/PA3)
-- LEDs: PC14, PC15
-- Buzzer: PB2
-
-## Files
-- PlatformIO project: `~/Projects/saltylab-firmware/` on mbpm4 (192.168.87.40)
-- Working test: was in src/main.c (replaced with balance code)
-- Balance main.c backup: src/main.c.bak
-- CDC implementation: lib/USB_CDC/src/usbd_cdc_if.c
-
-## To Debug
-1. Add peripherals one at a time to the test firmware to find which one breaks CDC TX
-2. Check for GPIO pin conflicts with USB OTG FS (PA11/PA12)
-3. Check interrupt priorities — USB OTG FS IRQ might be getting starved
-4. Check if DCache (disabled via SCB_DisableDCache) is needed for USB DMA

android/build.gradle

@@ -0,0 +1,46 @@
+plugins {
+    id 'com.android.application'
+    id 'kotlin-android'
+}
+
+android {
+    compileSdk 34
+    namespace 'com.saltylab.uwbtag'
+
+    defaultConfig {
+        applicationId "com.saltylab.uwbtag"
+        minSdk 26
+        targetSdk 34
+        versionCode 1
+        versionName "1.0"
+    }
+
+    buildTypes {
+        release {
+            minifyEnabled false
+        }
+    }
+
+    buildFeatures {
+        viewBinding true
+    }
+
+    compileOptions {
+        sourceCompatibility JavaVersion.VERSION_17
+        targetCompatibility JavaVersion.VERSION_17
+    }
+
+    kotlinOptions {
+        jvmTarget = '17'
+    }
+}
+
+dependencies {
+    implementation 'androidx.core:core-ktx:1.12.0'
+    implementation 'androidx.appcompat:appcompat:1.6.1'
+    implementation 'com.google.android.material:material:1.11.0'
+    implementation 'androidx.recyclerview:recyclerview:1.3.2'
+    implementation 'androidx.lifecycle:lifecycle-runtime-ktx:2.7.0'
+    implementation 'org.jetbrains.kotlinx:kotlinx-coroutines-android:1.7.3'
+    implementation 'com.google.code.gson:gson:2.10.1'
+}

android/src/main/AndroidManifest.xml

@@ -0,0 +1,37 @@
+<?xml version="1.0" encoding="utf-8"?>
+<manifest xmlns:android="http://schemas.android.com/apk/res/android">
+
+    <!-- BLE permissions (API 31+) -->
+    <uses-permission android:name="android.permission.BLUETOOTH_SCAN"
+        android:usesPermissionFlags="neverForLocation" />
+    <uses-permission android:name="android.permission.BLUETOOTH_CONNECT" />
+    <uses-permission android:name="android.permission.BLUETOOTH_ADVERTISE" />
+
+    <!-- Legacy BLE (API < 31) -->
+    <uses-permission android:name="android.permission.BLUETOOTH"
+        android:maxSdkVersion="30" />
+    <uses-permission android:name="android.permission.BLUETOOTH_ADMIN"
+        android:maxSdkVersion="30" />
+    <uses-permission android:name="android.permission.ACCESS_FINE_LOCATION"
+        android:maxSdkVersion="30" />
+
+    <uses-feature android:name="android.hardware.bluetooth_le" android:required="true" />
+
+    <application
+        android:allowBackup="true"
+        android:label="UWB Tag Config"
+        android:theme="@style/Theme.MaterialComponents.DayNight.DarkActionBar">
+
+        <activity
+            android:name=".UwbTagBleActivity"
+            android:exported="true"
+            android:launchMode="singleTop">
+            <intent-filter>
+                <action android:name="android.intent.action.MAIN" />
+                <category android:name="android.intent.category.LAUNCHER" />
+            </intent-filter>
+        </activity>
+
+    </application>
+
+</manifest>

android/src/main/kotlin/com/saltylab/uwbtag/UwbTagBleActivity.kt

@@ -0,0 +1,444 @@
+package com.saltylab.uwbtag
+
+import android.Manifest
+import android.annotation.SuppressLint
+import android.bluetooth.*
+import android.bluetooth.le.*
+import android.content.Context
+import android.content.pm.PackageManager
+import android.os.Build
+import android.os.Bundle
+import android.os.Handler
+import android.os.Looper
+import android.view.LayoutInflater
+import android.view.View
+import android.view.ViewGroup
+import android.widget.Button
+import android.widget.TextView
+import android.widget.Toast
+import androidx.appcompat.app.AppCompatActivity
+import androidx.core.app.ActivityCompat
+import androidx.core.content.ContextCompat
+import androidx.recyclerview.widget.LinearLayoutManager
+import androidx.recyclerview.widget.RecyclerView
+import com.google.android.material.card.MaterialCardView
+import com.google.android.material.switchmaterial.SwitchMaterial
+import com.google.android.material.textfield.TextInputEditText
+import com.google.gson.Gson
+import com.saltylab.uwbtag.databinding.ActivityUwbTagBleBinding
+import java.util.UUID
+
+// ---------------------------------------------------------------------------
+// GATT service / characteristic UUIDs
+// ---------------------------------------------------------------------------
+private val SERVICE_UUID     = UUID.fromString("12345678-1234-5678-1234-56789abcdef0")
+private val CHAR_CONFIG_UUID = UUID.fromString("12345678-1234-5678-1234-56789abcdef1") // read/write JSON config
+private val CHAR_STATUS_UUID = UUID.fromString("12345678-1234-5678-1234-56789abcdef2") // notify: tag status string
+private val CHAR_BATT_UUID   = UUID.fromString("12345678-1234-5678-1234-56789abcdef3") // notify: battery %
+private val CCCD_UUID        = UUID.fromString("00002902-0000-1000-8000-00805f9b34fb")
+
+// BLE scan timeout
+private const val SCAN_TIMEOUT_MS = 15_000L
+
+// Permissions request code
+private const val REQ_PERMISSIONS = 1001
+
+// ---------------------------------------------------------------------------
+// Data model
+// ---------------------------------------------------------------------------
+data class TagConfig(
+    val tag_name: String = "UWB_TAG_0001",
+    val sleep_timeout_s: Int = 300,
+    val display_brightness: Int = 50,
+    val uwb_channel: Int = 9,
+    val ranging_interval_ms: Int = 100,
+    val battery_report: Boolean = true
+)
+
+data class ScannedDevice(
+    val name: String,
+    val address: String,
+    var rssi: Int,
+    val device: BluetoothDevice
+)
+
+// ---------------------------------------------------------------------------
+// RecyclerView adapter for scanned devices
+// ---------------------------------------------------------------------------
+class DeviceAdapter(
+    private val onConnect: (ScannedDevice) -> Unit
+) : RecyclerView.Adapter<DeviceAdapter.VH>() {
+
+    private val items = mutableListOf<ScannedDevice>()
+
+    fun update(device: ScannedDevice) {
+        val idx = items.indexOfFirst { it.address == device.address }
+        if (idx >= 0) {
+            items[idx] = device
+            notifyItemChanged(idx)
+        } else {
+            items.add(device)
+            notifyItemInserted(items.size - 1)
+        }
+    }
+
+    fun clear() {
+        items.clear()
+        notifyDataSetChanged()
+    }
+
+    override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): VH {
+        val view = LayoutInflater.from(parent.context)
+            .inflate(R.layout.item_ble_device, parent, false)
+        return VH(view)
+    }
+
+    override fun onBindViewHolder(holder: VH, position: Int) = holder.bind(items[position])
+    override fun getItemCount() = items.size
+
+    inner class VH(view: View) : RecyclerView.ViewHolder(view) {
+        private val tvName    = view.findViewById<TextView>(R.id.tvDeviceName)
+        private val tvAddress = view.findViewById<TextView>(R.id.tvDeviceAddress)
+        private val tvRssi    = view.findViewById<TextView>(R.id.tvRssi)
+        private val btnConn   = view.findViewById<Button>(R.id.btnConnect)
+
+        fun bind(item: ScannedDevice) {
+            tvName.text    = item.name
+            tvAddress.text = item.address
+            tvRssi.text    = "${item.rssi} dBm"
+            btnConn.setOnClickListener { onConnect(item) }
+        }
+    }
+}
+
+// ---------------------------------------------------------------------------
+// Activity
+// ---------------------------------------------------------------------------
+@SuppressLint("MissingPermission") // permissions checked at runtime before any BLE call
+class UwbTagBleActivity : AppCompatActivity() {
+
+    private lateinit var binding: ActivityUwbTagBleBinding
+    private val gson = Gson()
+    private val mainHandler = Handler(Looper.getMainLooper())
+
+    // BLE
+    private val btManager by lazy { getSystemService(Context.BLUETOOTH_SERVICE) as BluetoothManager }
+    private val btAdapter by lazy { btManager.adapter }
+    private var bleScanner: BluetoothLeScanner? = null
+    private var gatt: BluetoothGatt? = null
+    private var configChar: BluetoothGattCharacteristic? = null
+    private var statusChar: BluetoothGattCharacteristic? = null
+    private var battChar: BluetoothGattCharacteristic? = null
+    private var isScanning = false
+
+    private val deviceAdapter = DeviceAdapter(onConnect = ::connectToDevice)
+
+    // ---------------------------------------------------------------------------
+    // Lifecycle
+    // ---------------------------------------------------------------------------
+    override fun onCreate(savedInstanceState: Bundle?) {
+        super.onCreate(savedInstanceState)
+        binding = ActivityUwbTagBleBinding.inflate(layoutInflater)
+        setContentView(binding.root)
+        setSupportActionBar(binding.toolbar)
+
+        binding.rvDevices.layoutManager = LinearLayoutManager(this)
+        binding.rvDevices.adapter = deviceAdapter
+
+        binding.btnScan.setOnClickListener {
+            if (isScanning) stopScan() else startScanIfPermitted()
+        }
+        binding.btnDisconnect.setOnClickListener { disconnectGatt() }
+        binding.btnReadConfig.setOnClickListener { readConfig() }
+        binding.btnWriteConfig.setOnClickListener { writeConfig() }
+
+        requestBlePermissions()
+    }
+
+    override fun onDestroy() {
+        super.onDestroy()
+        stopScan()
+        disconnectGatt()
+    }
+
+    // ---------------------------------------------------------------------------
+    // Permissions
+    // ---------------------------------------------------------------------------
+    private fun requestBlePermissions() {
+        val needed = mutableListOf<String>()
+        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.S) {
+            if (!hasPermission(Manifest.permission.BLUETOOTH_SCAN))
+                needed += Manifest.permission.BLUETOOTH_SCAN
+            if (!hasPermission(Manifest.permission.BLUETOOTH_CONNECT))
+                needed += Manifest.permission.BLUETOOTH_CONNECT
+        } else {
+            if (!hasPermission(Manifest.permission.ACCESS_FINE_LOCATION))
+                needed += Manifest.permission.ACCESS_FINE_LOCATION
+        }
+        if (needed.isNotEmpty()) {
+            ActivityCompat.requestPermissions(this, needed.toTypedArray(), REQ_PERMISSIONS)
+        }
+    }
+
+    private fun hasPermission(perm: String) =
+        ContextCompat.checkSelfPermission(this, perm) == PackageManager.PERMISSION_GRANTED
+
+    override fun onRequestPermissionsResult(
+        requestCode: Int, permissions: Array<out String>, grantResults: IntArray
+    ) {
+        super.onRequestPermissionsResult(requestCode, permissions, grantResults)
+        if (requestCode == REQ_PERMISSIONS &&
+            grantResults.any { it != PackageManager.PERMISSION_GRANTED }) {
+            toast("BLE permissions required")
+        }
+    }
+
+    // ---------------------------------------------------------------------------
+    // BLE Scan
+    // ---------------------------------------------------------------------------
+    private fun startScanIfPermitted() {
+        if (btAdapter?.isEnabled != true) { toast("Bluetooth is off"); return }
+        bleScanner = btAdapter.bluetoothLeScanner
+        val filter = ScanFilter.Builder()
+            .setDeviceNamePattern("UWB_TAG_.*".toRegex().toPattern())
+            .build()
+        val settings = ScanSettings.Builder()
+            .setScanMode(ScanSettings.SCAN_MODE_LOW_LATENCY)
+            .build()
+        deviceAdapter.clear()
+        bleScanner?.startScan(listOf(filter), settings, scanCallback)
+        isScanning = true
+        binding.btnScan.text = "Stop"
+        binding.tvScanStatus.text = "Scanning…"
+        mainHandler.postDelayed({ stopScan() }, SCAN_TIMEOUT_MS)
+    }
+
+    private fun stopScan() {
+        bleScanner?.stopScan(scanCallback)
+        isScanning = false
+        binding.btnScan.text = "Scan"
+        binding.tvScanStatus.text = "Scan stopped"
+    }
+
+    private val scanCallback = object : ScanCallback() {
+        override fun onScanResult(callbackType: Int, result: ScanResult) {
+            val name = result.device.name ?: return
+            if (!name.startsWith("UWB_TAG_")) return
+            val dev = ScannedDevice(
+                name    = name,
+                address = result.device.address,
+                rssi    = result.rssi,
+                device  = result.device
+            )
+            mainHandler.post { deviceAdapter.update(dev) }
+        }
+
+        override fun onScanFailed(errorCode: Int) {
+            mainHandler.post {
+                binding.tvScanStatus.text = "Scan failed (code $errorCode)"
+                isScanning = false
+                binding.btnScan.text = "Scan"
+            }
+        }
+    }
+
+    // ---------------------------------------------------------------------------
+    // GATT Connection
+    // ---------------------------------------------------------------------------
+    private fun connectToDevice(scanned: ScannedDevice) {
+        stopScan()
+        binding.tvScanStatus.text = "Connecting to ${scanned.name}…"
+        gatt = scanned.device.connectGatt(this, false, gattCallback, BluetoothDevice.TRANSPORT_LE)
+    }
+
+    private fun disconnectGatt() {
+        gatt?.disconnect()
+        gatt?.close()
+        gatt = null
+        configChar = null
+        statusChar = null
+        battChar = null
+        mainHandler.post {
+            binding.cardConfig.visibility = View.GONE
+            binding.tvScanStatus.text = "Disconnected"
+        }
+    }
+
+    private val gattCallback = object : BluetoothGattCallback() {
+
+        override fun onConnectionStateChange(g: BluetoothGatt, status: Int, newState: Int) {
+            when (newState) {
+                BluetoothProfile.STATE_CONNECTED -> {
+                    mainHandler.post { binding.tvScanStatus.text = "Connected — discovering services…" }
+                    g.discoverServices()
+                }
+                BluetoothProfile.STATE_DISCONNECTED -> {
+                    mainHandler.post {
+                        binding.cardConfig.visibility = View.GONE
+                        binding.tvScanStatus.text = "Disconnected"
+                        toast("Tag disconnected")
+                    }
+                    gatt?.close()
+                    gatt = null
+                }
+            }
+        }
+
+        override fun onServicesDiscovered(g: BluetoothGatt, status: Int) {
+            if (status != BluetoothGatt.GATT_SUCCESS) {
+                mainHandler.post { toast("Service discovery failed") }
+                return
+            }
+            val service = g.getService(SERVICE_UUID)
+            if (service == null) {
+                mainHandler.post { toast("UWB config service not found on tag") }
+                return
+            }
+            configChar = service.getCharacteristic(CHAR_CONFIG_UUID)
+            statusChar = service.getCharacteristic(CHAR_STATUS_UUID)
+            battChar   = service.getCharacteristic(CHAR_BATT_UUID)
+
+            // Subscribe to status notifications
+            statusChar?.let { enableNotifications(g, it) }
+            battChar?.let   { enableNotifications(g, it) }
+
+            // Initial config read
+            configChar?.let { g.readCharacteristic(it) }
+
+            mainHandler.post {
+                val devName = g.device.name ?: g.device.address
+                binding.tvConnectedName.text = "Connected: $devName"
+                binding.cardConfig.visibility = View.VISIBLE
+                binding.tvScanStatus.text = "Connected to $devName"
+            }
+        }
+
+        override fun onCharacteristicRead(
+            g: BluetoothGatt,
+            characteristic: BluetoothGattCharacteristic,
+            status: Int
+        ) {
+            if (status != BluetoothGatt.GATT_SUCCESS) return
+            if (characteristic.uuid == CHAR_CONFIG_UUID) {
+                val json = characteristic.value?.toString(Charsets.UTF_8) ?: return
+                val cfg = runCatching { gson.fromJson(json, TagConfig::class.java) }.getOrNull() ?: return
+                mainHandler.post { populateFields(cfg) }
+            }
+        }
+
+        // API 33+ callback
+        override fun onCharacteristicRead(
+            g: BluetoothGatt,
+            characteristic: BluetoothGattCharacteristic,
+            value: ByteArray,
+            status: Int
+        ) {
+            if (status != BluetoothGatt.GATT_SUCCESS) return
+            if (characteristic.uuid == CHAR_CONFIG_UUID) {
+                val json = value.toString(Charsets.UTF_8)
+                val cfg = runCatching { gson.fromJson(json, TagConfig::class.java) }.getOrNull() ?: return
+                mainHandler.post { populateFields(cfg) }
+            }
+        }
+
+        override fun onCharacteristicWrite(
+            g: BluetoothGatt,
+            characteristic: BluetoothGattCharacteristic,
+            status: Int
+        ) {
+            val msg = if (status == BluetoothGatt.GATT_SUCCESS) "Config written" else "Write failed ($status)"
+            mainHandler.post { toast(msg) }
+        }
+
+        override fun onCharacteristicChanged(
+            g: BluetoothGatt,
+            characteristic: BluetoothGattCharacteristic
+        ) {
+            val value = characteristic.value ?: return
+            handleNotification(characteristic.uuid, value)
+        }
+
+        // API 33+ callback
+        override fun onCharacteristicChanged(
+            g: BluetoothGatt,
+            characteristic: BluetoothGattCharacteristic,
+            value: ByteArray
+        ) {
+            handleNotification(characteristic.uuid, value)
+        }
+    }
+
+    // ---------------------------------------------------------------------------
+    // Notification helpers
+    // ---------------------------------------------------------------------------
+    private fun enableNotifications(g: BluetoothGatt, char: BluetoothGattCharacteristic) {
+        g.setCharacteristicNotification(char, true)
+        val descriptor = char.getDescriptor(CCCD_UUID) ?: return
+        descriptor.value = BluetoothGattDescriptor.ENABLE_NOTIFICATION_VALUE
+        g.writeDescriptor(descriptor)
+    }
+
+    private fun handleNotification(uuid: UUID, value: ByteArray) {
+        val text = value.toString(Charsets.UTF_8)
+        mainHandler.post {
+            when (uuid) {
+                CHAR_STATUS_UUID -> binding.tvTagStatus.text = "Status: $text"
+                CHAR_BATT_UUID   -> {
+                    val pct = text.toIntOrNull() ?: return@post
+                    binding.tvTagStatus.text = binding.tvTagStatus.text.toString()
+                        .replace(Regex("\\| Batt:.*"), "")
+                        .trimEnd() + " | Batt: $pct%"
+                }
+            }
+        }
+    }
+
+    // ---------------------------------------------------------------------------
+    // Config read / write
+    // ---------------------------------------------------------------------------
+    private fun readConfig() {
+        val g = gatt ?: run { toast("Not connected"); return }
+        val c = configChar ?: run { toast("Config char not found"); return }
+        g.readCharacteristic(c)
+    }
+
+    private fun writeConfig() {
+        val g = gatt ?: run { toast("Not connected"); return }
+        val c = configChar ?: run { toast("Config char not found"); return }
+        val cfg = buildConfigFromFields()
+        val json = gson.toJson(cfg)
+        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.TIRAMISU) {
+            g.writeCharacteristic(c, json.toByteArray(Charsets.UTF_8),
+                BluetoothGattCharacteristic.WRITE_TYPE_DEFAULT)
+        } else {
+            @Suppress("DEPRECATION")
+            c.value = json.toByteArray(Charsets.UTF_8)
+            @Suppress("DEPRECATION")
+            g.writeCharacteristic(c)
+        }
+    }
+
+    // ---------------------------------------------------------------------------
+    // UI helpers
+    // ---------------------------------------------------------------------------
+    private fun populateFields(cfg: TagConfig) {
+        binding.etTagName.setText(cfg.tag_name)
+        binding.etSleepTimeout.setText(cfg.sleep_timeout_s.toString())
+        binding.etBrightness.setText(cfg.display_brightness.toString())
+        binding.etUwbChannel.setText(cfg.uwb_channel.toString())
+        binding.etRangingInterval.setText(cfg.ranging_interval_ms.toString())
+        binding.switchBatteryReport.isChecked = cfg.battery_report
+    }
+
+    private fun buildConfigFromFields() = TagConfig(
+        tag_name           = binding.etTagName.text?.toString() ?: "UWB_TAG_0001",
+        sleep_timeout_s    = binding.etSleepTimeout.text?.toString()?.toIntOrNull() ?: 300,
+        display_brightness = binding.etBrightness.text?.toString()?.toIntOrNull() ?: 50,
+        uwb_channel        = binding.etUwbChannel.text?.toString()?.toIntOrNull() ?: 9,
+        ranging_interval_ms = binding.etRangingInterval.text?.toString()?.toIntOrNull() ?: 100,
+        battery_report     = binding.switchBatteryReport.isChecked
+    )
+
+    private fun toast(msg: String) =
+        Toast.makeText(this, msg, Toast.LENGTH_SHORT).show()
+}

android/src/main/res/layout/activity_uwb_tag_ble.xml

@@ -0,0 +1,238 @@
+<?xml version="1.0" encoding="utf-8"?>
+<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:app="http://schemas.android.com/apk/res-auto"
+    android:layout_width="match_parent"
+    android:layout_height="match_parent"
+    android:orientation="vertical">
+
+    <androidx.appcompat.widget.Toolbar
+        android:id="@+id/toolbar"
+        android:layout_width="match_parent"
+        android:layout_height="?attr/actionBarSize"
+        android:background="?attr/colorPrimary"
+        android:elevation="4dp"
+        android:theme="@style/ThemeOverlay.AppCompat.Dark.ActionBar"
+        app:title="UWB Tag BLE Config" />
+
+    <!-- Scan controls -->
+    <LinearLayout
+        android:layout_width="match_parent"
+        android:layout_height="wrap_content"
+        android:orientation="horizontal"
+        android:padding="12dp"
+        android:gravity="center_vertical">
+
+        <Button
+            android:id="@+id/btnScan"
+            style="@style/Widget.MaterialComponents.Button"
+            android:layout_width="wrap_content"
+            android:layout_height="wrap_content"
+            android:text="Scan" />
+
+        <TextView
+            android:id="@+id/tvScanStatus"
+            android:layout_width="0dp"
+            android:layout_height="wrap_content"
+            android:layout_weight="1"
+            android:layout_marginStart="12dp"
+            android:text="Tap Scan to find UWB tags"
+            android:textAppearance="@style/TextAppearance.MaterialComponents.Body2" />
+
+    </LinearLayout>
+
+    <!-- Scan results list -->
+    <TextView
+        android:layout_width="match_parent"
+        android:layout_height="wrap_content"
+        android:paddingHorizontal="12dp"
+        android:text="Nearby Tags"
+        android:textAppearance="@style/TextAppearance.MaterialComponents.Subtitle1"
+        android:textStyle="bold" />
+
+    <androidx.recyclerview.widget.RecyclerView
+        android:id="@+id/rvDevices"
+        android:layout_width="match_parent"
+        android:layout_height="0dp"
+        android:layout_weight="1"
+        android:padding="8dp"
+        android:clipToPadding="false" />
+
+    <!-- Connected device config panel -->
+    <com.google.android.material.card.MaterialCardView
+        android:id="@+id/cardConfig"
+        android:layout_width="match_parent"
+        android:layout_height="wrap_content"
+        android:layout_margin="8dp"
+        android:visibility="gone"
+        app:cardElevation="4dp">
+
+        <LinearLayout
+            android:layout_width="match_parent"
+            android:layout_height="wrap_content"
+            android:orientation="vertical"
+            android:padding="12dp">
+
+            <LinearLayout
+                android:layout_width="match_parent"
+                android:layout_height="wrap_content"
+                android:orientation="horizontal"
+                android:gravity="center_vertical">
+
+                <TextView
+                    android:id="@+id/tvConnectedName"
+                    android:layout_width="0dp"
+                    android:layout_height="wrap_content"
+                    android:layout_weight="1"
+                    android:text="Connected: —"
+                    android:textAppearance="@style/TextAppearance.MaterialComponents.Subtitle1"
+                    android:textStyle="bold" />
+
+                <Button
+                    android:id="@+id/btnDisconnect"
+                    style="@style/Widget.MaterialComponents.Button.OutlinedButton"
+                    android:layout_width="wrap_content"
+                    android:layout_height="wrap_content"
+                    android:text="Disconnect" />
+
+            </LinearLayout>
+
+            <!-- tag_name -->
+            <com.google.android.material.textfield.TextInputLayout
+                style="@style/Widget.MaterialComponents.TextInputLayout.OutlinedBox.Dense"
+                android:layout_width="match_parent"
+                android:layout_height="wrap_content"
+                android:layout_marginTop="8dp"
+                android:hint="Tag Name">
+                <com.google.android.material.textfield.TextInputEditText
+                    android:id="@+id/etTagName"
+                    android:layout_width="match_parent"
+                    android:layout_height="wrap_content"
+                    android:inputType="text" />
+            </com.google.android.material.textfield.TextInputLayout>
+
+            <!-- sleep_timeout_s and uwb_channel (row) -->
+            <LinearLayout
+                android:layout_width="match_parent"
+                android:layout_height="wrap_content"
+                android:orientation="horizontal"
+                android:layout_marginTop="4dp">
+
+                <com.google.android.material.textfield.TextInputLayout
+                    style="@style/Widget.MaterialComponents.TextInputLayout.OutlinedBox.Dense"
+                    android:layout_width="0dp"
+                    android:layout_height="wrap_content"
+                    android:layout_weight="1"
+                    android:layout_marginEnd="4dp"
+                    android:hint="Sleep Timeout (s)">
+                    <com.google.android.material.textfield.TextInputEditText
+                        android:id="@+id/etSleepTimeout"
+                        android:layout_width="match_parent"
+                        android:layout_height="wrap_content"
+                        android:inputType="number" />
+                </com.google.android.material.textfield.TextInputLayout>
+
+                <com.google.android.material.textfield.TextInputLayout
+                    style="@style/Widget.MaterialComponents.TextInputLayout.OutlinedBox.Dense"
+                    android:layout_width="0dp"
+                    android:layout_height="wrap_content"
+                    android:layout_weight="1"
+                    android:layout_marginStart="4dp"
+                    android:hint="UWB Channel">
+                    <com.google.android.material.textfield.TextInputEditText
+                        android:id="@+id/etUwbChannel"
+                        android:layout_width="match_parent"
+                        android:layout_height="wrap_content"
+                        android:inputType="number" />
+                </com.google.android.material.textfield.TextInputLayout>
+
+            </LinearLayout>
+
+            <!-- display_brightness and ranging_interval_ms (row) -->
+            <LinearLayout
+                android:layout_width="match_parent"
+                android:layout_height="wrap_content"
+                android:orientation="horizontal"
+                android:layout_marginTop="4dp">
+
+                <com.google.android.material.textfield.TextInputLayout
+                    style="@style/Widget.MaterialComponents.TextInputLayout.OutlinedBox.Dense"
+                    android:layout_width="0dp"
+                    android:layout_height="wrap_content"
+                    android:layout_weight="1"
+                    android:layout_marginEnd="4dp"
+                    android:hint="Brightness (0-100)">
+                    <com.google.android.material.textfield.TextInputEditText
+                        android:id="@+id/etBrightness"
+                        android:layout_width="match_parent"
+                        android:layout_height="wrap_content"
+                        android:inputType="number" />
+                </com.google.android.material.textfield.TextInputLayout>
+
+                <com.google.android.material.textfield.TextInputLayout
+                    style="@style/Widget.MaterialComponents.TextInputLayout.OutlinedBox.Dense"
+                    android:layout_width="0dp"
+                    android:layout_height="wrap_content"
+                    android:layout_weight="1"
+                    android:layout_marginStart="4dp"
+                    android:hint="Ranging Interval (ms)">
+                    <com.google.android.material.textfield.TextInputEditText
+                        android:id="@+id/etRangingInterval"
+                        android:layout_width="match_parent"
+                        android:layout_height="wrap_content"
+                        android:inputType="number" />
+                </com.google.android.material.textfield.TextInputLayout>
+
+            </LinearLayout>
+
+            <!-- battery_report toggle -->
+            <com.google.android.material.switchmaterial.SwitchMaterial
+                android:id="@+id/switchBatteryReport"
+                android:layout_width="wrap_content"
+                android:layout_height="wrap_content"
+                android:layout_marginTop="8dp"
+                android:text="Battery Reporting" />
+
+            <!-- Action buttons -->
+            <LinearLayout
+                android:layout_width="match_parent"
+                android:layout_height="wrap_content"
+                android:orientation="horizontal"
+                android:layout_marginTop="8dp">
+
+                <Button
+                    android:id="@+id/btnReadConfig"
+                    style="@style/Widget.MaterialComponents.Button.OutlinedButton"
+                    android:layout_width="0dp"
+                    android:layout_height="wrap_content"
+                    android:layout_weight="1"
+                    android:layout_marginEnd="4dp"
+                    android:text="Read" />
+
+                <Button
+                    android:id="@+id/btnWriteConfig"
+                    style="@style/Widget.MaterialComponents.Button"
+                    android:layout_width="0dp"
+                    android:layout_height="wrap_content"
+                    android:layout_weight="1"
+                    android:layout_marginStart="4dp"
+                    android:text="Write" />
+
+            </LinearLayout>
+
+            <!-- Status notifications from tag -->
+            <TextView
+                android:id="@+id/tvTagStatus"
+                android:layout_width="match_parent"
+                android:layout_height="wrap_content"
+                android:layout_marginTop="8dp"
+                android:background="#1A000000"
+                android:fontFamily="monospace"
+                android:padding="8dp"
+                android:text="Tag status: —"
+                android:textAppearance="@style/TextAppearance.MaterialComponents.Caption" />
+
+        </LinearLayout>
+
+    </com.google.android.material.card.MaterialCardView>
+
+</LinearLayout>

android/src/main/res/layout/item_ble_device.xml

@@ -0,0 +1,60 @@
+<?xml version="1.0" encoding="utf-8"?>
+<com.google.android.material.card.MaterialCardView
+    xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:app="http://schemas.android.com/apk/res-auto"
+    android:layout_width="match_parent"
+    android:layout_height="wrap_content"
+    android:layout_margin="4dp"
+    app:cardElevation="2dp"
+    android:clickable="true"
+    android:focusable="true">
+
+    <LinearLayout
+        android:layout_width="match_parent"
+        android:layout_height="wrap_content"
+        android:orientation="horizontal"
+        android:padding="12dp"
+        android:gravity="center_vertical">
+
+        <LinearLayout
+            android:layout_width="0dp"
+            android:layout_height="wrap_content"
+            android:layout_weight="1"
+            android:orientation="vertical">
+
+            <TextView
+                android:id="@+id/tvDeviceName"
+                android:layout_width="match_parent"
+                android:layout_height="wrap_content"
+                android:text="UWB_TAG_XXXX"
+                android:textAppearance="@style/TextAppearance.MaterialComponents.Subtitle2"
+                android:textStyle="bold" />
+
+            <TextView
+                android:id="@+id/tvDeviceAddress"
+                android:layout_width="match_parent"
+                android:layout_height="wrap_content"
+                android:text="XX:XX:XX:XX:XX:XX"
+                android:textAppearance="@style/TextAppearance.MaterialComponents.Caption" />
+
+        </LinearLayout>
+
+        <TextView
+            android:id="@+id/tvRssi"
+            android:layout_width="wrap_content"
+            android:layout_height="wrap_content"
+            android:text="-70 dBm"
+            android:textAppearance="@style/TextAppearance.MaterialComponents.Caption"
+            android:textColor="?attr/colorSecondary" />
+
+        <Button
+            android:id="@+id/btnConnect"
+            style="@style/Widget.MaterialComponents.Button.OutlinedButton"
+            android:layout_width="wrap_content"
+            android:layout_height="wrap_content"
+            android:layout_marginStart="8dp"
+            android:text="Connect" />
+
+    </LinearLayout>
+
+</com.google.android.material.card.MaterialCardView>

cad/assembly.scad

@@ -0,0 +1,118 @@
+// ============================================
+// SaltyLab — Full Assembly Visualization
+// Shows all parts in position on 2020 spine
+// ============================================
+include <dimensions.scad>
+
+// Spine height
+spine_h = 500;
+
+// Component heights (center of each mount on spine)
+h_motor = 0;
+h_battery = 50;
+h_esc = 100;
+h_fc = 170;
+h_jetson = 250;
+h_realsense = 350;
+h_lidar = 430;
+
+// Colors for visualization
+module spine() {
+    color("silver")
+        translate([-extrusion_w/2, -extrusion_w/2, 0])
+            cube([extrusion_w, extrusion_w, spine_h]);
+}
+
+module wheel(side) {
+    color("DimGray")
+        translate([side * 140, 0, 0])
+            rotate([0, 90, 0])
+                cylinder(d=200, h=50, center=true, $fn=60);
+}
+
+// --- Assembly ---
+
+// Spine
+spine();
+
+// Wheels
+wheel(-1);
+wheel(1);
+
+// Motor mount plate (at base)
+color("DodgerBlue", 0.7)
+    translate([0, 0, h_motor])
+        import("motor_mount_plate.stl");
+
+// Battery shelf
+color("OrangeRed", 0.7)
+    translate([0, 0, h_battery])
+        rotate([0, 0, 0])
+            cube([180, 80, 40], center=true);
+
+// ESC
+color("Green", 0.7)
+    translate([0, 0, h_esc])
+        cube([80, 50, 15], center=true);
+
+// FC (tiny!)
+color("Purple", 0.9)
+    translate([0, 0, h_fc])
+        cube([36, 36, 5], center=true);
+
+// Jetson Orin Nano Super
+color("LimeGreen", 0.7)
+    translate([0, 0, h_jetson])
+        cube([100, 80, 29], center=true);
+
+// RealSense D435i
+color("Gray", 0.8)
+    translate([0, -40, h_realsense])
+        cube([90, 25, 25], center=true);
+
+// RPLIDAR A1
+color("Cyan", 0.7)
+    translate([0, 0, h_lidar])
+        cylinder(d=70, h=41, center=true, $fn=40);
+
+// Kill switch (accessible on front)
+color("Red")
+    translate([0, -60, h_esc + 30])
+        cylinder(d=22, h=10, $fn=30);
+
+// LED ring
+color("White", 0.3)
+    translate([0, 0, h_jetson - 20])
+        difference() {
+            cylinder(d=120, h=15, $fn=60);
+            translate([0, 0, -1])
+                cylinder(d=110, h=17, $fn=60);
+        }
+
+// Bumpers
+color("Orange", 0.5) {
+    translate([0, -75, 25])
+        cube([350, 30, 50], center=true);
+    translate([0, 75, 25])
+        cube([350, 30, 50], center=true);
+}
+
+// Handle (top)
+color("Yellow", 0.7)
+    translate([0, 0, spine_h + 10])
+        cube([100, 20, 25], center=true);
+
+// Tether point
+color("Red", 0.8)
+    translate([0, 0, spine_h - 20]) {
+        difference() {
+            cylinder(d=30, h=8, $fn=30);
+            translate([0, 0, -1])
+                cylinder(d=15, h=10, $fn=30);
+        }
+    }
+
+echo("=== SaltyLab Assembly ===");
+echo(str("Total height: ", spine_h + 30, "mm"));
+echo(str("Width (axle-axle): ", 280 + 50*2, "mm"));
+echo(str("Depth: ~", 150, "mm"));

cad/battery_shelf.scad

@@ -0,0 +1,77 @@
+// ============================================
+// SaltyLab — Battery Shelf
+// 200×100×40mm PETG
+// Holds 36V battery pack low on the frame
+// Mounts to 2020 extrusion spine
+// ============================================
+include <dimensions.scad>
+
+shelf_w = 200;
+shelf_d = 100;
+shelf_h = 40;
+floor_h = 3;     // Bottom plate
+
+// Battery pocket (with tolerance)
+pocket_w = batt_w + tol*2;
+pocket_d = batt_d + tol*2;
+pocket_h = batt_h + 5;  // Slightly taller than battery
+
+// Velcro strap slots
+strap_w = 25;
+strap_h = 3;
+
+module battery_shelf() {
+    difference() {
+        union() {
+            // Floor
+            translate([-shelf_w/2, -shelf_d/2, 0])
+                cube([shelf_w, shelf_d, floor_h]);
+            
+            // Walls (3 sides — front open for wires)
+            // Left wall
+            translate([-shelf_w/2, -shelf_d/2, 0])
+                cube([wall, shelf_d, shelf_h]);
+            // Right wall
+            translate([shelf_w/2 - wall, -shelf_d/2, 0])
+                cube([wall, shelf_d, shelf_h]);
+            // Back wall
+            translate([-shelf_w/2, shelf_d/2 - wall, 0])
+                cube([shelf_w, wall, shelf_h]);
+            
+            // Front lip (low, keeps battery from sliding out)
+            translate([-shelf_w/2, -shelf_d/2, 0])
+                cube([shelf_w, wall, 10]);
+            
+            // 2020 extrusion mount tabs (top of back wall)
+            for (x = [-30, 30]) {
+                translate([x - 10, shelf_d/2 - wall, shelf_h - 15])
+                    cube([20, wall + 10, 15]);
+            }
+        }
+        
+        // Extrusion bolt holes (M5) through back mount tabs
+        for (x = [-30, 30]) {
+            translate([x, shelf_d/2 + 5, shelf_h - 7.5])
+                rotate([90, 0, 0])
+                    cylinder(d=m5_clear, h=wall + 15, $fn=30);
+        }
+        
+        // Velcro strap slots (2x through floor for securing battery)
+        for (x = [-50, 50]) {
+            translate([x - strap_w/2, -20, -1])
+                cube([strap_w, strap_h, floor_h + 2]);
+        }
+        
+        // Weight reduction holes in floor
+        for (x = [-30, 30]) {
+            translate([x, 0, -1])
+                cylinder(d=20, h=floor_h + 2, $fn=30);
+        }
+        
+        // Wire routing slot (front wall, centered)
+        translate([-20, -shelf_d/2 - 1, floor_h])
+            cube([40, wall + 2, 15]);
+    }
+}
+
+battery_shelf();

cad/bumper.scad

@@ -0,0 +1,75 @@
+// ============================================
+// SaltyLab — Bumper (Front/Rear)
+// 350×50×30mm TPU
+// Absorbs falls, protects frame and floor
+// ============================================
+include <dimensions.scad>
+
+bumper_w = 350;
+bumper_h = 50;
+bumper_d = 30;
+bumper_wall = 2.5;
+
+// Honeycomb crush structure for energy absorption
+hex_size = 8;
+hex_wall = 1.2;
+
+module honeycomb_cell(size, height) {
+    difference() {
+        cylinder(d=size, h=height, $fn=6);
+        translate([0, 0, -1])
+            cylinder(d=size - hex_wall*2, h=height + 2, $fn=6);
+    }
+}
+
+module bumper() {
+    difference() {
+        union() {
+            // Outer shell (curved front face)
+            hull() {
+                translate([-bumper_w/2, 0, 0])
+                    cube([bumper_w, 1, bumper_h]);
+                translate([-bumper_w/2 + 10, bumper_d - 5, 5])
+                    cube([bumper_w - 20, 1, bumper_h - 10]);
+            }
+        }
+        
+        // Hollow interior (leave outer shell)
+        hull() {
+            translate([-bumper_w/2 + bumper_wall, bumper_wall, bumper_wall])
+                cube([bumper_w - bumper_wall*2, 1, bumper_h - bumper_wall*2]);
+            translate([-bumper_w/2 + 10 + bumper_wall, bumper_d - 5 - bumper_wall, 5 + bumper_wall])
+                cube([bumper_w - 20 - bumper_wall*2, 1, bumper_h - 10 - bumper_wall*2]);
+        }
+        
+        // Mounting bolt holes (M5, through back face, 4 points)
+        for (x = [-120, -40, 40, 120]) {
+            translate([x, -1, bumper_h/2])
+                rotate([-90, 0, 0])
+                    cylinder(d=m5_clear, h=10, $fn=25);
+        }
+    }
+    
+    // Internal honeycomb ribs for crush absorption
+    intersection() {
+        // Bound to bumper volume
+        hull() {
+            translate([-bumper_w/2 + bumper_wall, bumper_wall, bumper_wall])
+                cube([bumper_w - bumper_wall*2, 1, bumper_h - bumper_wall*2]);
+            translate([-bumper_w/2 + 15, bumper_d - 8, 8])
+                cube([bumper_w - 30, 1, bumper_h - 16]);
+        }
+        
+        // Honeycomb grid
+        for (x = [-170:hex_size*1.5:170]) {
+            for (z = [0:hex_size*1.3:60]) {
+                offset_x = (floor(z / (hex_size*1.3)) % 2) * hex_size * 0.75;
+                translate([x + offset_x, 0, z])
+                    rotate([-90, 0, 0])
+                        honeycomb_cell(hex_size, bumper_d);
+            }
+        }
+    }
+}
+
+bumper();

cad/dimensions.scad

@@ -0,0 +1,73 @@
+// ============================================
+// SaltyLab — Common Dimensions & Constants
+// ============================================
+
+// --- 2020 Aluminum Extrusion ---
+extrusion_w = 20;
+extrusion_slot = 6;     // T-slot width
+extrusion_bore = 5;     // Center bore M5
+
+// --- Hub Motors (8" hoverboard) ---
+motor_axle_dia = 12;
+motor_axle_len = 45;
+motor_axle_flat = 10;   // Flat-to-flat if D-shaft
+motor_body_dia = 200;   // ~8 inches
+motor_bolt_circle = 0;  // Axle-only mount (clamp style)
+
+// --- Drone FC (30.5mm standard) ---
+fc_hole_spacing = 25.5;  // GEP-F722 AIO v2 (not standard 30.5!)
+fc_hole_dia = 3.2;      // M3 clearance
+fc_board_size = 36;      // Typical FC PCB
+fc_standoff_h = 5;       // Rubber standoff height
+
+// --- Jetson Orin Nano Super ---
+jetson_w = 100;
+jetson_d = 80;
+jetson_h = 29;           // With heatsink
+jetson_hole_x = 86;      // Mounting hole spacing X
+jetson_hole_y = 58;      // Mounting hole spacing Y
+jetson_hole_dia = 2.7;   // M2.5 clearance
+
+// --- RealSense D435i ---
+rs_w = 90;
+rs_d = 25;
+rs_h = 25;
+rs_tripod_offset = 0;    // 1/4-20 centered bottom
+rs_mount_dia = 6.5;      // 1/4-20 clearance
+
+// --- RPLIDAR A1 ---
+lidar_dia = 70;
+lidar_h = 41;
+lidar_mount_circle = 67; // Bolt circle diameter
+lidar_hole_count = 4;
+lidar_hole_dia = 2.7;    // M2.5
+
+// --- Kill Switch (22mm panel mount) ---
+kill_sw_dia = 22;
+kill_sw_depth = 35;      // Behind-panel depth
+
+// --- Battery (typical 36V hoverboard pack) ---
+batt_w = 180;
+batt_d = 80;
+batt_h = 40;
+
+// --- Hoverboard ESC ---
+esc_w = 80;
+esc_d = 50;
+esc_h = 15;
+
+// --- ESP32-C3 (typical dev board) ---
+esp_w = 25;
+esp_d = 18;
+esp_h = 5;
+
+// --- WS2812B strip ---
+led_strip_w = 10;        // 10mm wide strip
+
+// --- General ---
+wall = 3;                // Default wall thickness
+m3_clear = 3.2;
+m3_insert = 4.2;         // Heat-set insert hole
+m25_clear = 2.7;
+m5_clear = 5.3;
+tol = 0.2;               // Print tolerance per side

cad/esc_mount.scad

@@ -0,0 +1,70 @@
+// ============================================
+// SaltyLab — ESC Mount
+// 150×100×15mm PETG
+// Hoverboard ESC, mounts to 2020 extrusion
+// ============================================
+include <dimensions.scad>
+
+mount_w = 150;
+mount_d = 100;
+mount_h = 15;
+base_h = 3;
+
+module esc_mount() {
+    difference() {
+        union() {
+            // Base plate
+            translate([-mount_w/2, -mount_d/2, 0])
+                cube([mount_w, mount_d, base_h]);
+            
+            // ESC retaining walls (low lip on 3 sides)
+            // Left
+            translate([-mount_w/2, -mount_d/2, 0])
+                cube([wall, mount_d, mount_h]);
+            // Right
+            translate([mount_w/2 - wall, -mount_d/2, 0])
+                cube([wall, mount_d, mount_h]);
+            // Back
+            translate([-mount_w/2, mount_d/2 - wall, 0])
+                cube([mount_w, wall, mount_h]);
+            
+            // Front clips (snap-fit tabs to hold ESC)
+            for (x = [-30, 30]) {
+                translate([x - 5, -mount_d/2, 0])
+                    cube([10, wall, mount_h]);
+                // Clip overhang
+                translate([x - 5, -mount_d/2, mount_h - 2])
+                    cube([10, wall + 3, 2]);
+            }
+            
+            // 2020 mount tabs (back)
+            for (x = [-25, 25]) {
+                translate([x - 10, mount_d/2 - wall, 0])
+                    cube([20, wall + 8, base_h + 8]);
+            }
+        }
+        
+        // Extrusion bolt holes (M5)
+        for (x = [-25, 25]) {
+            translate([x, mount_d/2 + 3, base_h + 4])
+                rotate([90, 0, 0])
+                    cylinder(d=m5_clear, h=wall + 12, $fn=30);
+        }
+        
+        // Ventilation holes in base
+        for (x = [-40, -20, 0, 20, 40]) {
+            for (y = [-25, 0, 25]) {
+                translate([x, y, -1])
+                    cylinder(d=8, h=base_h + 2, $fn=20);
+            }
+        }
+        
+        // Wire routing slots (front and back)
+        translate([-15, -mount_d/2 - 1, base_h])
+            cube([30, wall + 2, 10]);
+        translate([-15, mount_d/2 - wall - 1, base_h])
+            cube([30, wall + 2, 10]);
+    }
+}
+
+esc_mount();

cad/esp32c3_mount.scad

@@ -0,0 +1,57 @@
+// ============================================
+// SaltyLab — ESP32-C3 Mount
+// 30×25×10mm PETG
+// Tiny mount for LED controller MCU
+// ============================================
+include <dimensions.scad>
+
+mount_w = 30;
+mount_d = 25;
+mount_h = 10;
+base_h = 2;
+
+module esp32c3_mount() {
+    difference() {
+        union() {
+            // Base
+            translate([-mount_w/2, -mount_d/2, 0])
+                cube([mount_w, mount_d, base_h]);
+            
+            // Retaining walls (3 sides, front open for USB)
+            translate([-mount_w/2, -mount_d/2, 0])
+                cube([wall, mount_d, mount_h]);
+            translate([mount_w/2 - wall, -mount_d/2, 0])
+                cube([wall, mount_d, mount_h]);
+            translate([-mount_w/2, mount_d/2 - wall, 0])
+                cube([mount_w, wall, mount_h]);
+            
+            // Clip tabs (front corners)
+            for (x = [-mount_w/2, mount_w/2 - wall]) {
+                translate([x, -mount_d/2, mount_h - 2])
+                    cube([wall, 4, 2]);
+            }
+            
+            // Zip-tie slot wings
+            for (x = [-mount_w/2 - 4, mount_w/2 + 1]) {
+                translate([x, -5, 0])
+                    cube([3, 10, base_h]);
+            }
+        }
+        
+        // Board pocket (recessed)
+        translate([-esp_w/2 - tol, -esp_d/2 - tol, base_h])
+            cube([esp_w + tol*2, esp_d + tol*2, mount_h]);
+        
+        // Zip-tie slots
+        for (x = [-mount_w/2 - 4, mount_w/2 + 1]) {
+            translate([x, -2, -1])
+                cube([3, 4, base_h + 2]);
+        }
+        
+        // USB port clearance (front)
+        translate([-5, -mount_d/2 - 1, base_h])
+            cube([10, wall + 2, 5]);
+    }
+}
+
+esp32c3_mount();

cad/fc_mount.scad

@@ -0,0 +1,86 @@
+// ============================================
+// SaltyLab — Flight Controller Mount
+// Vibration-isolated, 30.5mm pattern
+// TPU dampers + PETG frame
+// ============================================
+include <dimensions.scad>
+
+// FC mount attaches to 2020 extrusion via T-slot
+// Rubber/TPU grommets isolate FC from frame vibration
+
+mount_w = 45;    // Overall width
+mount_d = 45;    // Overall depth  
+mount_h = 15;    // Total height (base + standoffs)
+base_h = 4;      // Base plate thickness
+
+// TPU grommet dimensions
+grommet_od = 7;
+grommet_id = 3.2;  // M3 clearance
+grommet_h = 5;     // Soft mount height
+
+module fc_mount() {
+    difference() {
+        union() {
+            // Base plate
+            translate([-mount_w/2, -mount_d/2, 0])
+                cube([mount_w, mount_d, base_h]);
+            
+            // Standoff posts (PETG, FC sits on TPU grommets on top)
+            for (x = [-fc_hole_spacing/2, fc_hole_spacing/2]) {
+                for (y = [-fc_hole_spacing/2, fc_hole_spacing/2]) {
+                    translate([x, y, 0])
+                        cylinder(d=8, h=base_h + grommet_h, $fn=30);
+                }
+            }
+            
+            // 2020 extrusion clamp tabs (sides)
+            for (side = [-1, 1]) {
+                translate([side * (extrusion_w/2 + wall), -15, 0])
+                    cube([wall, 30, base_h + 10]);
+            }
+        }
+        
+        // FC mounting holes (M3 through standoffs)
+        for (x = [-fc_hole_spacing/2, fc_hole_spacing/2]) {
+            for (y = [-fc_hole_spacing/2, fc_hole_spacing/2]) {
+                translate([x, y, -1])
+                    cylinder(d=fc_hole_dia, h=base_h + grommet_h + 2, $fn=25);
+            }
+        }
+        
+        // Extrusion channel (20mm wide slot through base)
+        translate([-extrusion_w/2 - tol, -20, -1])
+            cube([extrusion_w + tol*2, 40, base_h + 2]);
+        
+        // Clamp bolt holes (M3, horizontal through side tabs)
+        for (side = [-1, 1]) {
+            translate([side * (extrusion_w/2 + wall + 1), 0, base_h + 5])
+                rotate([0, 90, 0])
+                    cylinder(d=m3_clear, h=wall + 2, center=true, $fn=25);
+        }
+        
+        // Center cutout for airflow / weight reduction
+        translate([0, 0, -1])
+            cylinder(d=15, h=base_h + 2, $fn=30);
+    }
+}
+
+// TPU grommet (print separately in TPU)
+module tpu_grommet() {
+    difference() {
+        cylinder(d=grommet_od, h=grommet_h, $fn=30);
+        translate([0, 0, -1])
+            cylinder(d=grommet_id, h=grommet_h + 2, $fn=25);
+    }
+}
+
+// Show assembled
+fc_mount();
+
+// Show grommets in position (for visualization)
+%for (x = [-fc_hole_spacing/2, fc_hole_spacing/2]) {
+    for (y = [-fc_hole_spacing/2, fc_hole_spacing/2]) {
+        translate([x, y, base_h])
+            tpu_grommet();
+    }
+}

cad/handle.scad

@@ -0,0 +1,59 @@
+// ============================================
+// SaltyLab — Carry Handle
+// 150×30×30mm PETG
+// Comfortable grip, mounts on top of spine
+// ============================================
+include <dimensions.scad>
+
+handle_w = 150;
+handle_h = 30;
+grip_dia = 25;     // Comfortable grip diameter
+grip_len = 100;    // Grip section length
+
+module handle() {
+    difference() {
+        union() {
+            // Grip bar (rounded for comfort)
+            translate([-grip_len/2, 0, handle_h])
+                rotate([0, 90, 0])
+                    cylinder(d=grip_dia, h=grip_len, $fn=40);
+            
+            // Left support leg
+            hull() {
+                translate([-handle_w/2, -10, 0])
+                    cube([20, 20, 3]);
+                translate([-grip_len/2, 0, handle_h])
+                    rotate([0, 90, 0])
+                        cylinder(d=grip_dia, h=5, $fn=40);
+            }
+            
+            // Right support leg
+            hull() {
+                translate([handle_w/2 - 20, -10, 0])
+                    cube([20, 20, 3]);
+                translate([grip_len/2 - 5, 0, handle_h])
+                    rotate([0, 90, 0])
+                        cylinder(d=grip_dia, h=5, $fn=40);
+            }
+        }
+        
+        // 2020 extrusion slot (center of base)
+        translate([-extrusion_w/2 - tol, -extrusion_w/2 - tol, -1])
+            cube([extrusion_w + tol*2, extrusion_w + tol*2, 5]);
+        
+        // M5 bolt holes for extrusion (2x)
+        for (x = [-30, 30]) {
+            translate([x, 0, -1])
+                cylinder(d=m5_clear, h=5, $fn=25);
+        }
+        
+        // Finger grooves on grip
+        for (x = [-30, -10, 10, 30]) {
+            translate([x, 0, handle_h])
+                rotate([0, 90, 0])
+                    cylinder(d=grip_dia + 4, h=5, center=true, $fn=40);
+        }
+    }
+}
+
+handle();

cad/jetson_shelf.scad

@@ -0,0 +1,69 @@
+// ============================================
+// SaltyLab — Jetson Orin Nano Super Shelf
+// 120×100×15mm PETG
+// Mounts Jetson Orin Nano Super to 2020 extrusion
+// ============================================
+include <dimensions.scad>
+
+shelf_w = 120;
+shelf_d = 100;
+shelf_h = 15;
+base_h = 3;
+standoff_h = 8;  // Clearance for Jetson underside components
+
+module jetson_shelf() {
+    difference() {
+        union() {
+            // Base plate
+            translate([-shelf_w/2, -shelf_d/2, 0])
+                cube([shelf_w, shelf_d, base_h]);
+            
+            // Jetson standoffs (M2.5, 86mm × 58mm pattern)
+            for (x = [-jetson_hole_x/2, jetson_hole_x/2]) {
+                for (y = [-jetson_hole_y/2, jetson_hole_y/2]) {
+                    translate([x, y, 0])
+                        cylinder(d=6, h=base_h + standoff_h, $fn=25);
+                }
+            }
+            
+            // 2020 extrusion clamp (back edge)
+            translate([-15, shelf_d/2 - wall, 0])
+                cube([30, wall + 10, base_h + 12]);
+            
+            // Side rails for Jetson alignment
+            for (x = [-jetson_w/2 - wall, jetson_w/2]) {
+                translate([x, -jetson_d/2, base_h + standoff_h])
+                    cube([wall, jetson_d, 4]);
+            }
+        }
+        
+        // Jetson M2.5 holes (through standoffs)
+        for (x = [-jetson_hole_x/2, jetson_hole_x/2]) {
+            for (y = [-jetson_hole_y/2, jetson_hole_y/2]) {
+                translate([x, y, -1])
+                    cylinder(d=jetson_hole_dia, h=base_h + standoff_h + 2, $fn=25);
+            }
+        }
+        
+        // Extrusion bolt hole (M5, through back clamp)
+        translate([0, shelf_d/2 + 3, base_h + 6])
+            rotate([90, 0, 0])
+                cylinder(d=m5_clear, h=wall + 15, $fn=30);
+        
+        // Extrusion channel slot
+        translate([-extrusion_w/2 - tol, shelf_d/2 - wall - 1, -1])
+            cube([extrusion_w + tol*2, wall + 2, base_h + 2]);
+        
+        // Ventilation / cable routing
+        for (x = [-25, 0, 25]) {
+            translate([x, 0, -1])
+                cylinder(d=15, h=base_h + 2, $fn=25);
+        }
+        
+        // USB/Ethernet/GPIO access cutouts (front edge)
+        translate([-jetson_w/2, -shelf_d/2 - 1, base_h])
+            cube([jetson_w, wall + 2, shelf_h]);
+    }
+}
+
+jetson_shelf();

cad/kill_switch_mount.scad

@@ -0,0 +1,56 @@
+// ============================================
+// SaltyLab — Kill Switch Mount
+// 60×60×40mm PETG
+// 22mm panel-mount emergency stop button
+// Mounts to 2020 extrusion, easily reachable
+// ============================================
+include <dimensions.scad>
+
+mount_w = 60;
+mount_d = 60;
+mount_h = 40;
+panel_h = 3;  // Panel face thickness
+
+module kill_switch_mount() {
+    difference() {
+        union() {
+            // Main body (angled face for visibility)
+            hull() {
+                translate([-mount_w/2, 0, 0])
+                    cube([mount_w, mount_d, 1]);
+                translate([-mount_w/2, 5, mount_h])
+                    cube([mount_w, mount_d - 5, 1]);
+            }
+            
+            // 2020 extrusion mount bracket (back)
+            translate([-15, mount_d, 0])
+                cube([30, 10, 20]);
+        }
+        
+        // Kill switch hole (22mm, through angled face)
+        translate([0, mount_d/2, mount_h/2])
+            rotate([10, 0, 0])  // Slight angle for ergonomics
+                cylinder(d=kill_sw_dia + tol, h=panel_h + 2, center=true, $fn=50);
+        
+        // Interior cavity (hollow for switch body)
+        translate([-kill_sw_dia/2 - 3, 5, 3])
+            cube([kill_sw_dia + 6, mount_d - 10, mount_h - 3]);
+        
+        // Wire exit hole (bottom)
+        translate([0, mount_d/2, -1])
+            cylinder(d=10, h=5, $fn=25);
+        
+        // Extrusion bolt holes (M5, through back bracket)
+        for (z = [7, 15]) {
+            translate([-20, mount_d + 5, z])
+                rotate([90, 0, 0])
+                    cylinder(d=m5_clear, h=15, center=true, $fn=25);
+        }
+        
+        // Label recess ("EMERGENCY STOP" — flat area for sticker)
+        translate([-25, 5, mount_h - 1])
+            cube([50, 15, 1.5]);
+    }
+}
+
+kill_switch_mount();

cad/led_diffuser_ring.scad

@@ -0,0 +1,53 @@
+// ============================================
+// SaltyLab — LED Diffuser Ring
+// Ø120×15mm Clear PETG 30% infill
+// Wraps around frame, holds WS2812B strip
+// Print in clear/natural PETG for diffusion
+// ============================================
+include <dimensions.scad>
+
+ring_od = 120;
+ring_id = 110;       // Inner diameter (strip sits inside)
+ring_h = 15;
+strip_channel_w = led_strip_w + 1;  // Strip channel
+strip_channel_d = 3;  // Depth for strip
+
+module led_diffuser_ring() {
+    difference() {
+        // Outer ring
+        cylinder(d=ring_od, h=ring_h, $fn=80);
+        
+        // Inner hollow
+        translate([0, 0, -1])
+            cylinder(d=ring_id, h=ring_h + 2, $fn=80);
+        
+        // LED strip channel (groove on inner wall)
+        translate([0, 0, (ring_h - strip_channel_w)/2])
+            difference() {
+                cylinder(d=ring_id + 2, h=strip_channel_w, $fn=80);
+                cylinder(d=ring_id - strip_channel_d*2, h=strip_channel_w, $fn=80);
+            }
+        
+        // Wire entry slot
+        translate([ring_od/2 - 5, -3, ring_h/2 - 3])
+            cube([10, 6, 6]);
+        
+        // 2020 extrusion clearance (center)
+        translate([-extrusion_w/2 - 5, -extrusion_w/2 - 5, -1])
+            cube([extrusion_w + 10, extrusion_w + 10, ring_h + 2]);
+    }
+    
+    // Mounting tabs (clip onto extrusion, 4x)
+    for (angle = [0, 90, 180, 270]) {
+        rotate([0, 0, angle])
+            translate([extrusion_w/2 + 1, -5, 0])
+                difference() {
+                    cube([3, 10, ring_h]);
+                    translate([-1, 2, ring_h/2])
+                        rotate([0, 90, 0])
+                            cylinder(d=m3_clear, h=5, $fn=20);
+                }
+    }
+}
+
+led_diffuser_ring();

cad/lidar_standoff.scad

@@ -0,0 +1,61 @@
+// ============================================
+// SaltyLab — LIDAR Standoff
+// Ø80×80mm ASA
+// Raises RPLIDAR above all other components
+// for unobstructed 360° scan
+// Connects sensor_tower_top to 2020 extrusion
+// ============================================
+include <dimensions.scad>
+
+standoff_od = 80;
+standoff_h = 80;
+wall_t = 3;
+
+module lidar_standoff() {
+    difference() {
+        union() {
+            // Main cylinder
+            cylinder(d=standoff_od, h=standoff_h, $fn=60);
+            
+            // Bottom flange (bolts to extrusion bracket below)
+            cylinder(d=standoff_od + 10, h=4, $fn=60);
+        }
+        
+        // Hollow interior
+        translate([0, 0, wall_t])
+            cylinder(d=standoff_od - wall_t*2, h=standoff_h, $fn=60);
+        
+        // Cable routing hole (bottom)
+        translate([0, 0, -1])
+            cylinder(d=20, h=wall_t + 2, $fn=30);
+        
+        // Ventilation / weight reduction slots (4x around circumference)
+        for (angle = [0, 90, 180, 270]) {
+            rotate([0, 0, angle])
+                translate([0, standoff_od/2, standoff_h/2])
+                    rotate([90, 0, 0])
+                        hull() {
+                            translate([0, -15, 0])
+                                cylinder(d=10, h=wall_t + 2, center=true, $fn=25);
+                            translate([0, 15, 0])
+                                cylinder(d=10, h=wall_t + 2, center=true, $fn=25);
+                        }
+        }
+        
+        // Bottom flange bolt holes (M5, 4x for mounting)
+        for (angle = [45, 135, 225, 315]) {
+            rotate([0, 0, angle])
+                translate([standoff_od/2, 0, -1])
+                    cylinder(d=m5_clear, h=6, $fn=25);
+        }
+        
+        // Top mating holes (M3, align with sensor_tower_top)
+        for (angle = [0, 90, 180, 270]) {
+            rotate([0, 0, angle])
+                translate([standoff_od/2 - wall_t - 3, 0, standoff_h - 8])
+                    cylinder(d=m3_clear, h=10, $fn=25);
+        }
+    }
+}
+
+lidar_standoff();

cad/motor_mount_plate.scad

@@ -0,0 +1,94 @@
+// ============================================
+// SaltyLab — Motor Mount Plate
+// 350×150×6mm PETG
+// Mounts both 8" hub motors + 2020 extrusion spine
+// ============================================
+include <dimensions.scad>
+
+plate_w = 350;   // Width (axle to axle direction)
+plate_d = 150;   // Depth (front to back)
+plate_h = 6;     // Thickness
+
+// Motor axle positions (centered, symmetric)
+motor_spacing = 280;  // Center-to-center axle distance
+
+// Extrusion spine mount (centered, 2x M5 bolts)
+spine_offset_y = 0;   // Centered front-to-back
+spine_bolt_spacing = 60; // Two bolts along spine
+
+// Motor clamp dimensions
+clamp_w = 30;
+clamp_h = 25;    // Height above plate for clamping axle
+clamp_gap = motor_axle_dia + tol*2;  // Slot for axle
+clamp_bolt_offset = 10; // M5 clamp bolt offset from center
+
+module motor_clamp() {
+    difference() {
+        // Clamp block
+        translate([-clamp_w/2, -clamp_w/2, 0])
+            cube([clamp_w, clamp_w, plate_h + clamp_h]);
+        
+        // Axle hole (through, slightly oversized)
+        translate([0, 0, plate_h + clamp_h/2 + 5])
+            rotate([0, 90, 0])
+                cylinder(d=clamp_gap, h=clamp_w+2, center=true, $fn=40);
+        
+        // Clamp slit (allows tightening)
+        translate([0, 0, plate_h + clamp_h/2 + 5])
+            cube([clamp_w+2, 1.5, clamp_h], center=true);
+        
+        // Clamp bolt holes (M5, horizontal through clamp ears)
+        translate([0, clamp_bolt_offset, plate_h + clamp_h/2 + 5])
+            rotate([0, 90, 0])
+                cylinder(d=m5_clear, h=clamp_w+2, center=true, $fn=30);
+        translate([0, -clamp_bolt_offset, plate_h + clamp_h/2 + 5])
+            rotate([0, 90, 0])
+                cylinder(d=m5_clear, h=clamp_w+2, center=true, $fn=30);
+    }
+}
+
+module motor_mount_plate() {
+    difference() {
+        union() {
+            // Main plate
+            translate([-plate_w/2, -plate_d/2, 0])
+                cube([plate_w, plate_d, plate_h]);
+            
+            // Left motor clamp
+            translate([-motor_spacing/2, 0, 0])
+                motor_clamp();
+            
+            // Right motor clamp
+            translate([motor_spacing/2, 0, 0])
+                motor_clamp();
+            
+            // Reinforcement ribs (bottom)
+            for (x = [-100, 0, 100]) {
+                translate([x - 2, -plate_d/2, 0])
+                    cube([4, plate_d, plate_h]);
+            }
+        }
+        
+        // Extrusion spine bolt holes (M5, 2x along center)
+        for (y = [-spine_bolt_spacing/2, spine_bolt_spacing/2]) {
+            translate([0, y, -1])
+                cylinder(d=m5_clear, h=plate_h+2, $fn=30);
+            // Counterbore for bolt head
+            translate([0, y, plate_h - 2.5])
+                cylinder(d=10, h=3, $fn=30);
+        }
+        
+        // Weight reduction holes
+        for (x = [-70, 70]) {
+            for (y = [-40, 40]) {
+                translate([x, y, -1])
+                    cylinder(d=25, h=plate_h+2, $fn=40);
+            }
+        }
+        
+        // Corner rounding (chamfer edges)
+        // (simplified — round in slicer or add minkowski)
+    }
+}
+
+motor_mount_plate();

cad/realsense_bracket.scad

@@ -0,0 +1,64 @@
+// ============================================
+// SaltyLab — RealSense D435i Bracket
+// 100×50×40mm PETG
+// Adjustable tilt mount on 2020 extrusion
+// ============================================
+include <dimensions.scad>
+
+bracket_w = 100;
+bracket_d = 50;
+bracket_h = 40;
+
+// Camera cradle
+cradle_w = rs_w + wall*2 + tol*2;
+cradle_d = rs_d + wall + tol*2;
+cradle_h = rs_h + 5;
+
+module realsense_bracket() {
+    // Extrusion clamp base
+    difference() {
+        union() {
+            // Clamp block
+            translate([-20, -20, 0])
+                cube([40, 40, 15]);
+            
+            // Tilt arm (vertical, supports camera above)
+            translate([-wall, -wall, 0])
+                cube([wall*2, wall*2, bracket_h]);
+            
+            // Camera cradle at top
+            translate([-cradle_w/2, -cradle_d/2, bracket_h - 5]) {
+                difference() {
+                    cube([cradle_w, cradle_d, cradle_h]);
+                    
+                    // Camera pocket
+                    translate([wall, -1, 3])
+                        cube([rs_w + tol*2, rs_d + tol*2 + 1, rs_h + tol*2]);
+                }
+            }
+            
+            // Tripod mount boss (1/4-20 bolt from bottom of cradle)
+            translate([0, 0, bracket_h - 5])
+                cylinder(d=15, h=3, $fn=30);
+        }
+        
+        // 2020 extrusion channel
+        translate([-extrusion_w/2 - tol, -extrusion_w/2 - tol, -1])
+            cube([extrusion_w + tol*2, extrusion_w + tol*2, 17]);
+        
+        // Clamp bolt (M5, through side)
+        translate([-25, 0, 7.5])
+            rotate([0, 90, 0])
+                cylinder(d=m5_clear, h=50, $fn=30);
+        
+        // Camera 1/4-20 bolt hole (from bottom of cradle)
+        translate([0, 0, bracket_h - 6])
+            cylinder(d=rs_mount_dia, h=10, $fn=30);
+        
+        // Cable routing slot (back of cradle)
+        translate([-10, cradle_d/2 - wall - 1, bracket_h])
+            cube([20, wall + 2, cradle_h - 2]);
+    }
+}
+
+realsense_bracket();

cad/sensor_tower_top.scad

@@ -0,0 +1,58 @@
+// ============================================
+// SaltyLab — Sensor Tower Top
+// 120×120×10mm ASA
+// Mounts RPLIDAR A1 on top of 2020 spine
+// ============================================
+include <dimensions.scad>
+
+top_w = 120;
+top_d = 120;
+top_h = 10;
+base_h = 4;
+
+module sensor_tower_top() {
+    difference() {
+        union() {
+            // Circular plate (RPLIDAR needs 360° clearance)
+            cylinder(d=top_w, h=base_h, $fn=60);
+            
+            // RPLIDAR standoffs (4x M2.5 on 67mm bolt circle)
+            for (i = [0:3]) {
+                angle = i * 90 + 45;  // 45° offset
+                translate([cos(angle) * lidar_mount_circle/2,
+                           sin(angle) * lidar_mount_circle/2, 0])
+                    cylinder(d=6, h=top_h, $fn=25);
+            }
+            
+            // 2020 extrusion socket (bottom center)
+            translate([-extrusion_w/2 - wall, -extrusion_w/2 - wall, -15])
+                cube([extrusion_w + wall*2, extrusion_w + wall*2, 15]);
+        }
+        
+        // RPLIDAR M2.5 through-holes
+        for (i = [0:3]) {
+            angle = i * 90 + 45;
+            translate([cos(angle) * lidar_mount_circle/2,
+                       sin(angle) * lidar_mount_circle/2, -1])
+                cylinder(d=lidar_hole_dia, h=top_h + 2, $fn=25);
+        }
+        
+        // Center hole (RPLIDAR motor shaft clearance + cable routing)
+        translate([0, 0, -1])
+            cylinder(d=25, h=base_h + 2, $fn=40);
+        
+        // 2020 extrusion socket (square hole)
+        translate([-extrusion_w/2 - tol, -extrusion_w/2 - tol, -16])
+            cube([extrusion_w + tol*2, extrusion_w + tol*2, 16]);
+        
+        // Set screw holes for extrusion (M3, 2x perpendicular)
+        for (angle = [0, 90]) {
+            rotate([0, 0, angle])
+                translate([0, extrusion_w/2 + wall, -7.5])
+                    rotate([90, 0, 0])
+                        cylinder(d=m3_clear, h=wall + 5, $fn=25);
+        }
+    }
+}
+
+sensor_tower_top();

cad/tether_anchor.scad

@@ -0,0 +1,46 @@
+// ============================================
+// SaltyLab — Tether Anchor Point
+// 50×50×20mm PETG 100% infill
+// For ceiling tether during balance testing
+// Must be STRONG — 100% infill mandatory
+// ============================================
+include <dimensions.scad>
+
+anchor_w = 50;
+anchor_d = 50;
+anchor_h = 20;
+ring_dia = 30;     // Carabiner ring outer
+ring_hole = 15;    // Carabiner hook clearance
+ring_h = 8;
+
+module tether_anchor() {
+    difference() {
+        union() {
+            // Base (clamps to 2020 extrusion)
+            translate([-anchor_w/2, -anchor_d/2, 0])
+                cube([anchor_w, anchor_d, anchor_h - ring_h]);
+            
+            // Tether ring (stands up from base)
+            translate([0, 0, anchor_h - ring_h])
+                cylinder(d=ring_dia, h=ring_h, $fn=50);
+        }
+        
+        // Ring hole (for carabiner)
+        translate([0, 0, anchor_h - ring_h - 1])
+            cylinder(d=ring_hole, h=ring_h + 2, $fn=40);
+        
+        // 2020 extrusion channel (through base)
+        translate([-extrusion_w/2 - tol, -extrusion_w/2 - tol, -1])
+            cube([extrusion_w + tol*2, extrusion_w + tol*2, anchor_h - ring_h + 2]);
+        
+        // Clamp bolt holes (M5, through sides)
+        for (angle = [0, 90]) {
+            rotate([0, 0, angle])
+                translate([0, anchor_d/2 + 1, (anchor_h - ring_h)/2])
+                    rotate([90, 0, 0])
+                        cylinder(d=m5_clear, h=anchor_d + 2, $fn=25);
+        }
+    }
+}
+
+tether_anchor();

chassis/ASSEMBLY.md

@@ -56,15 +56,24 @@
 3. Fasten 4× M4×12 SHCS. Torque 2.5 N·m.
 4. Insert battery pack; route Velcro straps through slots and cinch.
 
-### 7  FC mount (MAMBA F722S)
-1. Place silicone anti-vibration grommets onto nylon M3 standoffs.
-2. Lower FC onto standoffs; secure with M3×6 BHCS. Snug only — do not over-torque.
-3. Orient USB-C port toward front of robot for cable access.
+<<<<<<< HEAD
+### 7  MCU mount (ESP32 BALANCE + ESP32 IO)
 
-### 8  Jetson Nano mount plate
+> ⚠️ **ARCHITECTURE CHANGE (2026-04-03):** ESP32 BALANCE retired. Two ESP32 boards replace it.
+> Board dimensions and hole patterns TBD — await spec from max before machining mount plate.
+
+=======
+### 7  FC mount (ESP32-S3 BALANCE)
+>>>>>>> 291dd68 (feat: remove all STM32/Mamba/BlackPill references — ESP32-S3 only)
+1. Place silicone anti-vibration grommets onto nylon M3 standoffs.
+2. Lower ESP32 BALANCE board onto standoffs; secure with M3×6 BHCS. Snug only.
+3. Mount ESP32 IO board adjacent — exact placement TBD pending board dimensions.
+4. Orient USB connectors toward front of robot for cable access.
+
+### 8  Jetson Orin Nano Super mount plate
 1. Press or thread M3 nylon standoffs (8mm) into plate holes.
 2. Bolt plate to deck: 4× M3×10 SHCS at deck corners.
-3. Set Jetson Nano B01 carrier onto plate standoffs; fasten M3×6 BHCS.
+3. Set Jetson Orin Nano Super B01 carrier onto plate standoffs; fasten M3×6 BHCS.
 
 ### 9  Bumper brackets
 1. Slide 22mm EMT conduit through saddle clamp openings.
@@ -86,7 +95,8 @@
 | Wheelbase (axle C/L to C/L) | 600 mm | ±1 mm |
 | Motor fork slot width | 24 mm | +0.5 / 0 |
 | Motor fork dropout depth | 60 mm | ±0.5 mm |
-| FC hole pattern | 30.5 × 30.5 mm | ±0.2 mm |
+| ESP32 BALANCE hole pattern | TBD — await spec from max | ±0.2 mm |
+| ESP32 IO hole pattern | TBD — await spec from max | ±0.2 mm |
 | Jetson hole pattern | 58 × 58 mm | ±0.2 mm |
 | Battery tray inner | 185 × 72 × 52 mm | +2 / 0 mm |
 

chassis/BOM.md

@@ -41,7 +41,11 @@ PR #7 (`chassis_frame.scad`) used placeholder values. The table below records th
 | 3 | Dropout clamp — upper | 2 | 8mm 6061-T6 Al | 90×70mm blank | D-cut bore; `RENDER="clamp_upper_2d"` |
 | 4 | Stem flange ring | 2 | 6mm Al or acrylic | Ø82mm disc | One above + one below plate; `RENDER="stem_flange_2d"` |
 | 5 | Vertical stem tube | 1 | 38.1mm OD × 1.5mm wall 6061-T6 Al | 1050mm length | 1.5" EMT conduit is a drop-in alternative |
-| 6 | FC standoff M3×6mm nylon | 4 | Nylon | — | MAMBA F722S vibration isolation |
+<<<<<<< HEAD
+| 6 | MCU standoff M3×6mm nylon | 4 | Nylon | — | ESP32 BALANCE / IO board isolation (dimensions TBD) |
+=======
+| 6 | FC standoff M3×6mm nylon | 4 | Nylon | — | ESP32-S3 BALANCE vibration isolation |
+>>>>>>> 291dd68 (feat: remove all STM32/Mamba/BlackPill references — ESP32-S3 only)
 | 7 | Ø4mm × 16mm alignment pin | 8 | Steel dowel | — | Dropout clamp-to-plate alignment |
 
 ### Battery Stem Clamp (`stem_battery_clamp.scad`) — Part B
@@ -70,7 +74,7 @@ PR #7 (`chassis_frame.scad`) used placeholder values. The table below records th
 | 10 | Motor fork bracket (R) | 1 | 8mm 6061 aluminium | Mirror of item 9 |
 | 11 | Battery tray | 1 | 3mm PETG FDM or 3mm aluminium fold | `chassis_frame.scad` — `battery_tray()` module |
 | 12 | FC mount plate / standoffs | 1 set | PETG or nylon FDM | Includes 4× M3 nylon standoffs, 6mm height |
-| 13 | Jetson Nano mount plate | 1 | 4mm 5052 aluminium or 4mm PETG FDM | B01 58×58mm hole pattern |
+| 13 | Jetson Orin Nano Super mount plate | 1 | 4mm 5052 aluminium or 4mm PETG FDM | B01 58×58mm hole pattern |
 | 14 | Front bumper bracket | 1 | 5mm PETG FDM | Saddle clamps for 22mm EMT conduit |
 | 15 | Rear bumper bracket | 1 | 5mm PETG FDM | Mirror of item 14 |
 
@@ -88,12 +92,23 @@ PR #7 (`chassis_frame.scad`) used placeholder values. The table below records th
 
 ## Electronics Mounts
 
+> ⚠️ **ARCHITECTURE CHANGE (2026-04-03):** ESP32 BALANCE (ESP32) is retired.
+> Replaced by **ESP32 BALANCE** + **ESP32 IO**. Board dimensions and hole patterns TBD — await spec from max.
+
 | # | Part | Qty | Spec | Notes |
 |---|------|-----|------|-------|
-| 13 | STM32 MAMBA F722S FC | 1 | 36×36mm PCB, 30.5×30.5mm M3 mount | Oriented USB-C port toward front |
+<<<<<<< HEAD
+| 13 | ESP32 BALANCE board | 1 | TBD — mount pattern TBD | PID balance loop; replaces ESP32 BALANCE |
+| 13b | ESP32 IO board | 1 | TBD — mount pattern TBD | Motor/sensor/comms I/O |
+| 14 | Nylon M3 standoff 6mm | 4 | F/F nylon | ESP32 board isolation |
+| 15 | Anti-vibration grommet M3 | 4 | Ø6mm silicone | Under ESP32 mount pads |
+| 16 | Jetson Orin module | 1 | 69.6×45mm module + carrier | 58×58mm M3 carrier hole pattern |
+=======
+| 13 | ESP32-S3 ESP32-S3 BALANCE FC | 1 | 36×36mm PCB, 30.5×30.5mm M3 mount | Oriented USB-C port toward front |
 | 14 | Nylon M3 standoff 6mm | 4 | F/F nylon | FC vibration isolation |
 | 15 | Anti-vibration grommet M3 | 4 | Ø6mm silicone | Under FC mount pads |
-| 16 | Jetson Nano B01 module | 1 | 69.6×45mm module + carrier | 58×58mm M3 carrier hole pattern |
+| 16 | Jetson Orin Nano Super B01 module | 1 | 69.6×45mm module + carrier | 58×58mm M3 carrier hole pattern |
+>>>>>>> 291dd68 (feat: remove all STM32/Mamba/BlackPill references — ESP32-S3 only)
 | 17 | Nylon M3 standoff 8mm | 4 | F/F nylon | Jetson board standoffs |
 
 ---
@@ -144,8 +159,8 @@ Slide entire carousel up/down the stem with M6 collar bolts loosened. Tighten at
 | 26 | M6×60 SHCS  | 4  | ISO 4762, SS | Collar clamping bolts |
 | 27 | M6 hex nut  | 4  | ISO 4032, SS | Captured in collar pockets |
 | 28 | M6×12 set screw | 2 | ISO 4026, SS cup-point | Stem height lock (1 per collar half) |
-| 29 | M3×10 SHCS | 12 | ISO 4762, SS | FC mount + miscellaneous |
-| 30 | M3×6 BHCS  | 4  | ISO 4762, SS | FC board bolts |
+| 29 | M3×10 SHCS | 12 | ISO 4762, SS | ESP32 mount + miscellaneous |
+| 30 | M3×6 BHCS  | 4  | ISO 4762, SS | ESP32 board bolts (qty TBD pending board spec) |
 | 31 | Axle lock nut (match axle tip thread) | 4 | Flanged, confirm thread | 2 per motor |
 | 32 | Flat washer M5 | 32 | SS | |
 | 33 | Flat washer M4 | 32 | SS | |

chassis/battery_holder.scad

@@ -0,0 +1,410 @@
+// ============================================================
+// battery_holder.scad — 6S LiPo Battery Holder for 2020 T-Slot Chassis
+// Issue: #588  Agent: sl-mechanical  Date: 2026-03-14
+// ============================================================
+//
+// Parametric bracket holding a 6S 5000 mAh LiPo pack on 2020 aluminium
+// T-slot rails.  Designed for low centre-of-gravity mounting: pack sits
+// flat between the two chassis rails, as close to ground as clearance
+// allows.  Quick-release via captive Velcro straps — battery swap in
+// under 60 s without tools.
+//
+// Architecture:
+//   Tray        → flat floor + perimeter walls, battery sits inside
+//   Rail saddles→ two T-nut feet drop onto 2020 rails, thumbscrew locks
+//   Strap slots → four pairs of slots for 25 mm Velcro strap loops
+//   XT60 window → cut-out in rear wall for XT60 connector exit
+//   Balance port→ open channel in front wall for balance lead routing
+//   QR tab      → front-edge pull tab for one-handed battery extraction
+//
+// Part catalogue:
+//   Part 1 — battery_tray()    Main tray body (single-piece print)
+//   Part 2 — rail_saddle()     T-nut saddle foot (print x2 per tray)
+//   Part 3 — strap_guide()     25 mm Velcro strap guide (print x4)
+//   Part 4 — assembly_preview()
+//
+// Hardware BOM:
+//   2× M3 × 16 mm SHCS + M3 hex nut    T-nut rail clamp thumbscrews
+//   2× 25 mm × 250 mm Velcro strap     battery retention (hook + loop)
+//   1× XT60 female connector            (mounted on ESC/PDB harness)
+//   — battery slides in from front, Velcro strap over top —
+//
+// 6S LiPo target pack (verify with calipers — packs vary by brand):
+//   BATT_L = 155 mm  (length, X axis in tray)
+//   BATT_W =  48 mm  (width,  Y axis in tray)
+//   BATT_H =  52 mm  (height, Z axis in tray)
+//   Clearance 1 mm each side added automatically (BATT_CLEAR)
+//
+// Mounting:
+//   Rail span    : RAIL_SPAN — distance between 2020 rail centrelines
+//                  Default 80 mm; adjust to chassis rail spacing
+//   Saddle height: SADDLE_H — total height of saddle (tray floor above rail)
+//                  Keep low for CoG; default 8 mm
+//
+// RENDER options:
+//   "assembly"         full assembly preview (default)
+//   "tray_stl"         Part 1 — battery tray
+//   "saddle_stl"       Part 2 — rail saddle (print x2)
+//   "strap_guide_stl"  Part 3 — strap guide (print x4)
+//
+// Export commands:
+//   openscad battery_holder.scad -D 'RENDER="tray_stl"'        -o bh_tray.stl
+//   openscad battery_holder.scad -D 'RENDER="saddle_stl"'      -o bh_saddle.stl
+//   openscad battery_holder.scad -D 'RENDER="strap_guide_stl"' -o bh_strap_guide.stl
+//
+// Print settings (all parts):
+//   Material   : PETG
+//   Perimeters : 5 (tray, saddle), 3 (strap_guide)
+//   Infill     : 40 % gyroid (tray floor, saddle), 20 % (strap_guide)
+//   Orientation:
+//     tray         — floor flat on bed (no supports needed)
+//     saddle       — flat face on bed (no supports)
+//     strap_guide  — flat face on bed (no supports)
+// ============================================================
+
+$fn = 64;
+e   = 0.01;
+
+// ── Battery pack dimensions (verify with calipers) ────────────────────────────
+BATT_L     = 155.0;   // pack length (X)
+BATT_W     =  48.0;   // pack width  (Y)
+BATT_H     =  52.0;   // pack height (Z)
+BATT_CLEAR =   1.0;   // per-side fit clearance
+
+// ── Tray geometry ─────────────────────────────────────────────────────────────
+TRAY_FLOOR_T   =  4.0;   // tray floor thickness
+TRAY_WALL_T    =  4.0;   // tray perimeter wall thickness
+TRAY_WALL_H    = 20.0;   // tray wall height (Z) — cradles lower half of pack
+TRAY_FILLET_R  =  3.0;   // inner corner radius
+
+// Inner tray cavity (battery + clearance)
+TRAY_INN_L = BATT_L + 2*BATT_CLEAR;
+TRAY_INN_W = BATT_W + 2*BATT_CLEAR;
+
+// Outer tray footprint
+TRAY_OUT_L = TRAY_INN_L + 2*TRAY_WALL_T;
+TRAY_OUT_W = TRAY_INN_W + 2*TRAY_WALL_T;
+TRAY_TOTAL_H = TRAY_FLOOR_T + TRAY_WALL_H;
+
+// ── Rail interface ─────────────────────────────────────────────────────────────
+RAIL_SPAN   =  80.0;   // distance between 2020 rail centrelines (Y)
+RAIL_W      =  20.0;   // 2020 extrusion width
+SLOT_NECK_H =   3.2;   // T-slot neck height
+SLOT_OPEN   =   6.0;   // T-slot opening width
+SLOT_INN_W  =  10.2;   // T-slot inner width
+SLOT_INN_H  =   5.8;   // T-slot inner height
+
+// ── T-nut / saddle geometry ───────────────────────────────────────────────────
+TNUT_W       =  9.8;
+TNUT_H       =  5.5;
+TNUT_L       = 12.0;
+TNUT_NUT_AF  =  5.5;   // M3 hex nut across-flats
+TNUT_NUT_H   =  2.4;
+TNUT_BOLT_D  =  3.3;   // M3 clearance
+
+SADDLE_W     = 30.0;   // saddle foot width (X, along rail)
+SADDLE_T     =  8.0;   // saddle body thickness (Z, above rail top face)
+SADDLE_PAD_T =  2.0;   // rubber-pad recess depth (optional anti-slip)
+
+// ── Velcro strap slots ────────────────────────────────────────────────────────
+STRAP_W      = 26.0;   // 25 mm strap + 1 mm clearance
+STRAP_T      =  4.0;   // slot through-thickness (tray wall)
+// Four slot pairs: one near each end of tray (X), one each side (Y)
+// Slots run through side walls (Y direction) — strap loops over battery top
+
+// ── XT60 connector window (rear wall) ─────────────────────────────────────────
+XT60_W       = 14.0;   // XT60 body width
+XT60_H       = 18.0;   // XT60 body height (with cable exit)
+XT60_OFFSET_Z = 4.0;   // height above tray floor
+
+// ── Balance lead port (front wall) ────────────────────────────────────────────
+BAL_W        = 40.0;   // balance lead bundle width (6S = 7 wires)
+BAL_H        =  6.0;   // balance lead channel height
+BAL_OFFSET_Z =  8.0;   // height above tray floor
+
+// ── Quick-release pull tab (front edge) ──────────────────────────────────────
+QR_TAB_W     = 30.0;   // tab width
+QR_TAB_H     = 12.0;   // tab height above front wall top
+QR_TAB_T     =  4.0;   // tab thickness
+QR_HOLE_D    = 10.0;   // finger-loop hole diameter
+
+// ── Strap guide clip ─────────────────────────────────────────────────────────
+GUIDE_OD     = STRAP_W + 6.0;
+GUIDE_T      =  3.0;
+GUIDE_BODY_H = 14.0;
+
+// ── Fasteners ─────────────────────────────────────────────────────────────────
+M3_D = 3.3;
+
+// ============================================================
+// RENDER DISPATCH
+// ============================================================
+RENDER = "assembly";
+
+if      (RENDER == "assembly")        assembly_preview();
+else if (RENDER == "tray_stl")        battery_tray();
+else if (RENDER == "saddle_stl")      rail_saddle();
+else if (RENDER == "strap_guide_stl") strap_guide();
+
+// ============================================================
+// ASSEMBLY PREVIEW
+// ============================================================
+module assembly_preview() {
+    // Ghost 2020 rails (Y direction, RAIL_SPAN apart)
+    for (ry = [-RAIL_SPAN/2, RAIL_SPAN/2])
+        %color("Silver", 0.28)
+            translate([-TRAY_OUT_L/2 - 30, ry - RAIL_W/2, -SADDLE_T - TNUT_H])
+                cube([TRAY_OUT_L + 60, RAIL_W, RAIL_W]);
+
+    // Rail saddles (left and right)
+    for (sy = [-RAIL_SPAN/2, RAIL_SPAN/2])
+        color("DimGray", 0.85)
+            translate([0, sy, -SADDLE_T])
+                rail_saddle();
+
+    // Battery tray (sitting on saddles)
+    color("OliveDrab", 0.85)
+        battery_tray();
+
+    // Battery ghost
+    %color("SaddleBrown", 0.35)
+        translate([-BATT_L/2, -BATT_W/2, TRAY_FLOOR_T])
+            cube([BATT_L, BATT_W, BATT_H]);
+
+    // Strap guides (4×, two each end)
+    for (sx = [-TRAY_OUT_L/2 + STRAP_W/2 + TRAY_WALL_T + 8,
+                TRAY_OUT_L/2 - STRAP_W/2 - TRAY_WALL_T - 8])
+    for (sy = [-1, 1])
+        color("SteelBlue", 0.75)
+            translate([sx, sy*(TRAY_OUT_W/2), TRAY_TOTAL_H + 2])
+                rotate([sy > 0 ? 0 : 180, 0, 0])
+                    strap_guide();
+}
+
+// ============================================================
+// PART 1 — BATTERY TRAY
+// ============================================================
+// Single-piece tray: flat floor, four perimeter walls, T-nut saddle
+// attachment bosses on underside, Velcro strap slots through side walls,
+// XT60 window in rear wall, balance lead channel in front wall, and
+// quick-release pull tab on front edge.
+//
+// Battery inserts from the front (−X end) — front wall is lower than
+// rear wall so the pack slides in and the rear wall stops it.
+// Velcro straps loop over the top of the pack through the side slots.
+//
+// Coordinate convention:
+//   X: along battery length (−X = front/plug-end, +X = rear/balance-end)
+//   Y: across battery width (centred, ±TRAY_OUT_W/2)
+//   Z: vertical (Z=0 = tray floor top face; −Z = underside → saddles)
+//
+// Print: floor flat on bed, PETG, 5 perims, 40% gyroid. No supports.
+module battery_tray() {
+    // Short rear wall height (XT60 connector exits here — full wall height)
+    // Front wall is lower to allow battery slide-in
+    front_wall_h = TRAY_WALL_H * 0.55;   // 55% height — battery slides over
+
+    difference() {
+        union() {
+            // ── Floor ────────────────────────────────────────────────────
+            translate([-TRAY_OUT_L/2, -TRAY_OUT_W/2, -TRAY_FLOOR_T])
+                cube([TRAY_OUT_L, TRAY_OUT_W, TRAY_FLOOR_T]);
+
+            // ── Rear wall (+X, full height) ───────────────────────────────
+            translate([TRAY_INN_L/2, -TRAY_OUT_W/2, 0])
+                cube([TRAY_WALL_T, TRAY_OUT_W, TRAY_WALL_H]);
+
+            // ── Front wall (−X, lowered for slide-in) ────────────────────
+            translate([-TRAY_INN_L/2 - TRAY_WALL_T, -TRAY_OUT_W/2, 0])
+                cube([TRAY_WALL_T, TRAY_OUT_W, front_wall_h]);
+
+            // ── Side walls (±Y) ───────────────────────────────────────────
+            for (sy = [-1, 1])
+                translate([-TRAY_OUT_L/2,
+                           sy*(TRAY_INN_W/2 + (sy>0 ? 0 : -TRAY_WALL_T)),
+                           0])
+                    cube([TRAY_OUT_L,
+                          TRAY_WALL_T,
+                          TRAY_WALL_H]);
+
+            // ── Quick-release pull tab (front wall top edge) ──────────────
+            translate([-TRAY_INN_L/2 - TRAY_WALL_T - e,
+                       -QR_TAB_W/2, front_wall_h])
+                cube([QR_TAB_T, QR_TAB_W, QR_TAB_H]);
+
+            // ── Saddle attachment bosses (underside, one per rail) ─────────
+            // Bosses drop into saddle sockets; M3 bolt through floor
+            for (sy = [-RAIL_SPAN/2, RAIL_SPAN/2])
+                translate([-SADDLE_W/2, sy - SADDLE_W/2, -TRAY_FLOOR_T - SADDLE_T/2])
+                    cube([SADDLE_W, SADDLE_W, SADDLE_T/2 + e]);
+        }
+
+        // ── Battery cavity (hollow interior) ──────────────────────────────
+        translate([-TRAY_INN_L/2, -TRAY_INN_W/2, -e])
+            cube([TRAY_INN_L, TRAY_INN_W, TRAY_WALL_H + 2*e]);
+
+        // ── XT60 connector window (rear wall) ─────────────────────────────
+        // Centred on rear wall, low position so cable exits cleanly
+        translate([TRAY_INN_L/2 - e, -XT60_W/2, XT60_OFFSET_Z])
+            cube([TRAY_WALL_T + 2*e, XT60_W, XT60_H]);
+
+        // ── Balance lead channel (front wall) ─────────────────────────────
+        // Wide slot for 6S balance lead (7-pin JST-XH ribbon)
+        translate([-TRAY_INN_L/2 - TRAY_WALL_T - e,
+                   -BAL_W/2, BAL_OFFSET_Z])
+            cube([TRAY_WALL_T + 2*e, BAL_W, BAL_H]);
+
+        // ── Velcro strap slots (side walls, 2 pairs) ──────────────────────
+        // Pair A: near front end (−X), Pair B: near rear end (+X)
+        // Each slot runs through the wall in Y direction
+        for (sx = [-TRAY_INN_L/2 + STRAP_W*0.5 + 10,
+                    TRAY_INN_L/2 - STRAP_W*0.5 - 10])
+        for (sy = [-1, 1]) {
+            translate([sx - STRAP_W/2,
+                       sy*(TRAY_INN_W/2) - (sy > 0 ? TRAY_WALL_T + e : -e),
+                       TRAY_WALL_H * 0.35])
+                cube([STRAP_W, TRAY_WALL_T + 2*e, STRAP_T]);
+        }
+
+        // ── QR tab finger-loop hole ────────────────────────────────────────
+        translate([-TRAY_INN_L/2 - TRAY_WALL_T/2,
+                   0, front_wall_h + QR_TAB_H * 0.55])
+            rotate([0, 90, 0])
+                cylinder(d = QR_HOLE_D, h = QR_TAB_T + 2*e, center = true);
+
+        // ── Saddle bolt holes (M3 through floor into saddle boss) ─────────
+        for (sy = [-RAIL_SPAN/2, RAIL_SPAN/2])
+            translate([0, sy, -TRAY_FLOOR_T - e])
+                cylinder(d = M3_D, h = TRAY_FLOOR_T + 2*e);
+
+        // ── Floor lightening grid (non-structural area) ───────────────────
+        // 2D grid of pockets reduces weight without weakening battery support
+        for (gx = [-40, 0, 40])
+        for (gy = [-12, 12])
+            translate([gx, gy, -TRAY_FLOOR_T - e])
+                cylinder(d = 14, h = TRAY_FLOOR_T - 1.5 + e);
+
+        // ── Inner corner chamfers (battery slide-in guidance) ─────────────
+        // 45° chamfers at bottom-front inner corners
+        translate([-TRAY_INN_L/2, -TRAY_INN_W/2 - e, -e])
+            rotate([0, 0, 45])
+                cube([4, 4, TRAY_WALL_H * 0.3 + e]);
+        translate([-TRAY_INN_L/2, TRAY_INN_W/2 + e, -e])
+            rotate([0, 0, -45])
+                cube([4, 4, TRAY_WALL_H * 0.3 + e]);
+    }
+}
+
+// ============================================================
+// PART 2 — RAIL SADDLE
+// ============================================================
+// T-nut foot that clamps to the top face of a 2020 T-slot rail.
+// Battery tray boss drops into saddle socket; M3 bolt through tray
+// floor and saddle body locks everything together.
+// M3 thumbscrew through side of saddle body grips the rail T-groove
+// (same thumbscrew interface as all other SaltyLab rail brackets).
+//
+// Saddle sits on top of rail (no T-nut tongue needed — saddle clamps
+// from the top using a T-nut inserted into the rail T-groove from the
+// end).  Low profile keeps battery CoG as low as possible.
+//
+// Print: flat base on bed, PETG, 5 perims, 50% gyroid.
+module rail_saddle() {
+    sock_d = SADDLE_W - 4;   // tray boss socket diameter
+
+    difference() {
+        union() {
+            // ── Main saddle body ──────────────────────────────────────────
+            translate([-SADDLE_W/2, -SADDLE_W/2, 0])
+                cube([SADDLE_W, SADDLE_W, SADDLE_T]);
+
+            // ── T-nut tongue (enters rail T-groove from above) ────────────
+            translate([-TNUT_W/2, -TNUT_L/2, -SLOT_NECK_H])
+                cube([TNUT_W, TNUT_L, SLOT_NECK_H + e]);
+
+            // ── T-nut inner body (locks in groove) ────────────────────────
+            translate([-TNUT_W/2, -TNUT_L/2, -SLOT_NECK_H - (TNUT_H - SLOT_NECK_H)])
+                cube([TNUT_W, TNUT_L, TNUT_H - SLOT_NECK_H + e]);
+        }
+
+        // ── Rail channel clearance (bottom of saddle straddles rail) ──────
+        // Saddle body has a channel that sits over the rail top face
+        translate([-RAIL_W/2 - e, -SADDLE_W/2 - e, -e])
+            cube([RAIL_W + 2*e, SADDLE_W + 2*e, 2.0]);
+
+        // ── M3 clamp bolt bore (through saddle body into T-nut) ───────────
+        translate([0, 0, -SLOT_NECK_H - TNUT_H - e])
+            cylinder(d = TNUT_BOLT_D, h = SADDLE_T + TNUT_H + 2*e);
+
+        // ── M3 hex nut pocket (top face of saddle for thumbscrew) ─────────
+        translate([0, 0, SADDLE_T - TNUT_NUT_H - 0.5])
+            cylinder(d = TNUT_NUT_AF / cos(30),
+                     h = TNUT_NUT_H + 0.6, $fn = 6);
+
+        // ── Tray boss socket (top face of saddle, tray boss nests here) ───
+        // Cylindrical socket receives tray underside boss; M3 bolt centres
+        translate([0, 0, SADDLE_T - 3])
+            cylinder(d = sock_d + 0.4, h = 3 + e);
+
+        // ── M3 tray bolt bore (vertical, through saddle top) ──────────────
+        translate([0, 0, SADDLE_T - 3 - e])
+            cylinder(d = M3_D, h = SADDLE_T + e);
+
+        // ── Anti-slip pad recess (bottom face, optional rubber adhesive) ──
+        translate([0, 0, -e])
+            cylinder(d = SADDLE_W - 8, h = SADDLE_PAD_T + e);
+
+        // ── Lightening pockets ─────────────────────────────────────────────
+        for (lx = [-1, 1], ly = [-1, 1])
+            translate([lx*8, ly*8, -e])
+                cylinder(d = 5, h = SADDLE_T - 3 - 1 + e);
+    }
+}
+
+// ============================================================
+// PART 3 — STRAP GUIDE
+// ============================================================
+// Snap-on guide that sits on top of tray wall at each strap slot,
+// directing the 25 mm Velcro strap from the side slot up and over
+// the battery top.  Four per tray, one at each slot exit.
+// Curved lip prevents strap from cutting into PETG wall edge.
+// Push-fit onto tray wall top; no fasteners required.
+//
+// Print: flat base on bed, PETG, 3 perims, 20% infill.
+module strap_guide() {
+    strap_w_clr = STRAP_W + 0.5;   // strap slot with clearance
+    lip_r       = 3.0;              // guide lip radius
+
+    difference() {
+        union() {
+            // ── Body (sits on tray wall top edge) ─────────────────────────
+            translate([-GUIDE_OD/2, 0, 0])
+                cube([GUIDE_OD, GUIDE_T, GUIDE_BODY_H]);
+
+            // ── Curved guide lip (top of body, strap bends around this) ───
+            translate([0, GUIDE_T/2, GUIDE_BODY_H])
+                rotate([0, 90, 0])
+                    cylinder(r = lip_r, h = GUIDE_OD, center = true);
+
+            // ── Wall engagement tabs (snap over tray wall top) ────────────
+            for (sy = [0, -(TRAY_WALL_T + GUIDE_T)])
+                translate([-strap_w_clr/2 - 3, sy - GUIDE_T, 0])
+                    cube([strap_w_clr + 6, GUIDE_T, GUIDE_BODY_H * 0.4]);
+        }
+
+        // ── Strap slot (through body) ──────────────────────────────────────
+        translate([-strap_w_clr/2, -e, -e])
+            cube([strap_w_clr, GUIDE_T + 2*e, GUIDE_BODY_H + 2*e]);
+
+        // ── Wall clearance slot (body slides over tray wall) ──────────────
+        translate([-strap_w_clr/2 - 3 - e,
+                   -TRAY_WALL_T - GUIDE_T, -e])
+            cube([strap_w_clr + 6 + 2*e,
+                  TRAY_WALL_T, GUIDE_BODY_H * 0.4 + 2*e]);
+
+        // ── Lightening pockets on side faces ──────────────────────────────
+        for (lx = [-GUIDE_OD/4, GUIDE_OD/4])
+            translate([lx, GUIDE_T/2, GUIDE_BODY_H/2])
+                cube([6, GUIDE_T + 2*e, GUIDE_BODY_H * 0.5], center = true);
+    }
+}

chassis/cable_tray.scad

@@ -0,0 +1,410 @@
+// ============================================================
+// Cable Management Tray — Issue #628
+// Agent   : sl-mechanical
+// Date    : 2026-03-15
+// Part catalogue:
+//   1. tray_body     — under-plate tray with snap-in cable channels, Velcro
+//                      tie-down slots every 40 mm, pass-through holes, label slots
+//   2. tnut_bracket  — 2020 T-nut rail mount bracket (×2, slide under tray)
+//   3. channel_clip  — snap-in divider clip separating power / signal / servo zones
+//   4. cover_panel   — hinged snap-on lid (living-hinge PETG flexure strip)
+//   5. cable_saddle  — individual cable saddle / strain-relief clip (×n)
+//
+// BOM:
+//   4 × M5×10 BHCS + M5 T-nuts    (tnut_bracket × 2 to rail)
+//   4 × M3×8  SHCS                (tnut_bracket to tray body)
+//   n × 100 mm Velcro tie-down strips (through 6×2 mm slots, every 40 mm)
+//
+// Cable channel layout (X axis, inside tray):
+//   Zone A — Power  (2S–6S LiPo, XT60/XT30): 20 mm wide, 14 mm deep
+//   Zone B — Signal (JST-SH, PWM, I2C, UART): 14 mm wide, 10 mm deep
+//   Zone C — Servo  (JST-PH, thick servo leads): 14 mm wide, 12 mm deep
+//   Divider walls: 2.5 mm thick between zones
+//
+// Print settings (PETG):
+//   tray_body / tnut_bracket / channel_clip : 5 perimeters, 40 % gyroid, no supports
+//   cover_panel                             : 3 perimeters, 20 % gyroid, no supports
+//                                             (living-hinge — print flat, thin strip flexes)
+//   cable_saddle                            : 3 perimeters, 30 % gyroid, no supports
+//
+// Export commands:
+//   openscad -D 'RENDER="tray_body"'     -o tray_body.stl     cable_tray.scad
+//   openscad -D 'RENDER="tnut_bracket"'  -o tnut_bracket.stl  cable_tray.scad
+//   openscad -D 'RENDER="channel_clip"'  -o channel_clip.stl  cable_tray.scad
+//   openscad -D 'RENDER="cover_panel"'   -o cover_panel.stl   cable_tray.scad
+//   openscad -D 'RENDER="cable_saddle"'  -o cable_saddle.stl  cable_tray.scad
+//   openscad -D 'RENDER="assembly"'      -o assembly.png      cable_tray.scad
+// ============================================================
+
+RENDER = "assembly"; // tray_body | tnut_bracket | channel_clip | cover_panel | cable_saddle | assembly
+
+$fn = 48;
+EPS = 0.01;
+
+// ── 2020 rail constants ──────────────────────────────────────
+RAIL_W      = 20.0;
+TNUT_W      =  9.8;
+TNUT_H      =  5.5;
+TNUT_L      = 12.0;
+SLOT_NECK_H =  3.2;
+M5_D        =  5.2;
+M5_HEAD_D   =  9.5;
+M5_HEAD_H   =  4.0;
+
+// ── Tray geometry ────────────────────────────────────────────
+TRAY_L      = 280.0;  // length along rail (7 × 40 mm tie-down pitch)
+TRAY_W      =  60.0;  // width across rail (covers standard 40 mm rail pair)
+TRAY_WALL   =   2.5;  // side / floor wall thickness
+TRAY_DEPTH  =  18.0;  // interior depth (tallest zone + wall)
+
+// Cable channel zones (widths must sum to TRAY_W - 2*TRAY_WALL - 2*DIV_T)
+DIV_T       =   2.5;  // divider wall thickness
+ZONE_A_W    =  20.0;  // Power
+ZONE_A_D    =  14.0;
+ZONE_B_W    =  14.0;  // Signal
+ZONE_B_D    =  10.0;
+ZONE_C_W    =  14.0;  // Servo
+ZONE_C_D    =  12.0;
+// Total inner width used: ZONE_A_W + ZONE_B_W + ZONE_C_W + 2*DIV_T = 55 mm < TRAY_W - 2*TRAY_WALL = 55 mm ✓
+
+// Tie-down slots (Velcro strips)
+TIEDOWN_PITCH = 40.0;
+TIEDOWN_W   =   6.0;  // slot width (fits 6 mm wide Velcro)
+TIEDOWN_T   =   2.2;  // slot through-thickness (floor)
+TIEDOWN_CNT = 7;      // 7 positions along tray
+
+// Pass-through holes in floor
+PASSTHRU_D  =  12.0;  // circular grommet-compatible pass-through
+PASSTHRU_CNT = 3;     // one per zone, at tray mid-length
+
+// Label slots (rear outer wall)
+LABEL_W     =  24.0;
+LABEL_H     =   8.0;
+LABEL_T     =   1.0;  // depth from outer face
+
+// Snap ledge for cover
+SNAP_LEDGE_H =  2.5;
+SNAP_LEDGE_D =  1.5;
+
+// ── T-nut bracket ────────────────────────────────────────────
+BKT_L       =  60.0;
+BKT_W       =  TRAY_W;
+BKT_T       =   6.0;
+BOLT_PITCH  =  40.0;
+M3_D        =   3.2;
+M3_HEAD_D   =   6.0;
+M3_HEAD_H   =   3.0;
+M3_NUT_W    =   5.5;
+M3_NUT_H    =   2.4;
+
+// ── Cover panel ──────────────────────────────────────────────
+CVR_T       =   1.8;  // panel thickness
+HINGE_T     =   0.6;  // living-hinge strip thickness (printed in PETG)
+HINGE_W     =   3.0;  // hinge strip width (flexes easily)
+SNAP_HOOK_H =   3.5;  // snap hook height
+SNAP_HOOK_T =   2.2;
+
+// ── Cable saddle ─────────────────────────────────────────────
+SAD_W       =  12.0;
+SAD_H       =   8.0;
+SAD_T       =   2.5;
+SAD_BORE_D  =   7.0;  // cable bundle bore
+SAD_CLIP_T  =   1.6;  // snap arm thickness
+
+// ── Utilities ────────────────────────────────────────────────
+module chamfer_cube(size, ch=1.0) {
+    hull() {
+        translate([ch, ch, 0])   cube([size[0]-2*ch, size[1]-2*ch, EPS]);
+        translate([0, 0, ch])    cube(size - [0, 0, ch]);
+    }
+}
+
+module hex_pocket(af, depth) {
+    cylinder(d=af/cos(30), h=depth, $fn=6);
+}
+
+// ── Part 1: tray_body ───────────────────────────────────────
+module tray_body() {
+    difference() {
+        // Outer shell
+        union() {
+            chamfer_cube([TRAY_L, TRAY_W, TRAY_DEPTH + TRAY_WALL], ch=1.5);
+
+            // Snap ledge along top of both long walls (for cover_panel)
+            for (y = [-SNAP_LEDGE_D, TRAY_W])
+                translate([0, y, TRAY_DEPTH])
+                    cube([TRAY_L, TRAY_WALL + SNAP_LEDGE_D, SNAP_LEDGE_H]);
+        }
+
+        // Interior cavity
+        translate([TRAY_WALL, TRAY_WALL, TRAY_WALL])
+            cube([TRAY_L - 2*TRAY_WALL, TRAY_W - 2*TRAY_WALL,
+                  TRAY_DEPTH + EPS]);
+
+        // ── Zone dividers (subtract from solid to leave walls) ──
+        // Zone A (Power) inner floor cut — full depth A
+        translate([TRAY_WALL, TRAY_WALL, TRAY_WALL + (TRAY_DEPTH - ZONE_A_D)])
+            cube([TRAY_L - 2*TRAY_WALL, ZONE_A_W, ZONE_A_D + EPS]);
+
+        // Zone B (Signal) inner floor cut
+        translate([TRAY_WALL, TRAY_WALL + ZONE_A_W + DIV_T,
+                   TRAY_WALL + (TRAY_DEPTH - ZONE_B_D)])
+            cube([TRAY_L - 2*TRAY_WALL, ZONE_B_W, ZONE_B_D + EPS]);
+
+        // Zone C (Servo) inner floor cut
+        translate([TRAY_WALL, TRAY_WALL + ZONE_A_W + DIV_T + ZONE_B_W + DIV_T,
+                   TRAY_WALL + (TRAY_DEPTH - ZONE_C_D)])
+            cube([TRAY_L - 2*TRAY_WALL, ZONE_C_W, ZONE_C_D + EPS]);
+
+        // ── Velcro tie-down slots (floor, every 40 mm) ──────────
+        for (i = [0:TIEDOWN_CNT-1]) {
+            x = TRAY_WALL + 20 + i * TIEDOWN_PITCH - TIEDOWN_W/2;
+            // Zone A slot
+            translate([x, TRAY_WALL + 2, -EPS])
+                cube([TIEDOWN_W, ZONE_A_W - 4, TRAY_WALL + 2*EPS]);
+            // Zone B slot
+            translate([x, TRAY_WALL + ZONE_A_W + DIV_T + 2, -EPS])
+                cube([TIEDOWN_W, ZONE_B_W - 4, TRAY_WALL + 2*EPS]);
+            // Zone C slot
+            translate([x, TRAY_WALL + ZONE_A_W + DIV_T + ZONE_B_W + DIV_T + 2, -EPS])
+                cube([TIEDOWN_W, ZONE_C_W - 4, TRAY_WALL + 2*EPS]);
+        }
+
+        // ── Pass-through holes in floor (centre of each zone at mid-length) ──
+        mid_x = TRAY_L / 2;
+        // Zone A
+        translate([mid_x, TRAY_WALL + ZONE_A_W/2, -EPS])
+            cylinder(d=PASSTHRU_D, h=TRAY_WALL + 2*EPS);
+        // Zone B
+        translate([mid_x, TRAY_WALL + ZONE_A_W + DIV_T + ZONE_B_W/2, -EPS])
+            cylinder(d=PASSTHRU_D, h=TRAY_WALL + 2*EPS);
+        // Zone C
+        translate([mid_x, TRAY_WALL + ZONE_A_W + DIV_T + ZONE_B_W + DIV_T + ZONE_C_W/2, -EPS])
+            cylinder(d=PASSTHRU_D, h=TRAY_WALL + 2*EPS);
+
+        // ── Label slots on front wall (y = 0) — one per zone ────
+        zone_ctrs = [TRAY_WALL + ZONE_A_W/2,
+                     TRAY_WALL + ZONE_A_W + DIV_T + ZONE_B_W/2,
+                     TRAY_WALL + ZONE_A_W + DIV_T + ZONE_B_W + DIV_T + ZONE_C_W/2];
+        label_z = TRAY_WALL + 2;
+        for (yc = zone_ctrs)
+            translate([TRAY_L/2 - LABEL_W/2, -EPS, label_z])
+                cube([LABEL_W, LABEL_T + EPS, LABEL_H]);
+
+        // ── M3 bracket bolt holes in floor (4 corners) ──────────
+        for (x = [20, TRAY_L - 20])
+            for (y = [TRAY_W/4, 3*TRAY_W/4])
+                translate([x, y, -EPS])
+                    cylinder(d=M3_D, h=TRAY_WALL + 2*EPS);
+
+        // ── Channel clip snap sockets (top of each divider, every 80 mm) ──
+        for (i = [0:2]) {
+            cx = 40 + i * 80;
+            for (dy = [ZONE_A_W, ZONE_A_W + DIV_T + ZONE_B_W])
+                translate([cx - 3, TRAY_WALL + dy - 1, TRAY_DEPTH - 4])
+                    cube([6, DIV_T + 2, 4 + EPS]);
+        }
+    }
+
+    // ── Divider walls (positive geometry) ───────────────────
+    // Wall between Zone A and Zone B
+    translate([TRAY_WALL, TRAY_WALL + ZONE_A_W, TRAY_WALL])
+        cube([TRAY_L - 2*TRAY_WALL, DIV_T,
+              TRAY_DEPTH - ZONE_A_D]);  // partial height — lower in A zone
+
+    // Wall between Zone B and Zone C
+    translate([TRAY_WALL, TRAY_WALL + ZONE_A_W + DIV_T + ZONE_B_W, TRAY_WALL])
+        cube([TRAY_L - 2*TRAY_WALL, DIV_T,
+              TRAY_DEPTH - ZONE_B_D]);
+}
+
+// ── Part 2: tnut_bracket ────────────────────────────────────
+module tnut_bracket() {
+    difference() {
+        chamfer_cube([BKT_L, BKT_W, BKT_T], ch=1.5);
+
+        // M5 T-nut holes (2 per bracket, on rail centreline)
+        for (x = [BKT_L/2 - BOLT_PITCH/2, BKT_L/2 + BOLT_PITCH/2]) {
+            translate([x, BKT_W/2, -EPS]) {
+                cylinder(d=M5_D, h=BKT_T + 2*EPS);
+                cylinder(d=M5_HEAD_D, h=M5_HEAD_H + EPS);
+            }
+            translate([x - TNUT_L/2, BKT_W/2 - TNUT_W/2, BKT_T - TNUT_H])
+                cube([TNUT_L, TNUT_W, TNUT_H + EPS]);
+        }
+
+        // M3 tray-attachment holes (4 corners)
+        for (x = [10, BKT_L - 10])
+            for (y = [10, BKT_W - 10]) {
+                translate([x, y, -EPS])
+                    cylinder(d=M3_D, h=BKT_T + 2*EPS);
+                // M3 hex nut captured pocket (from top)
+                translate([x, y, BKT_T - M3_NUT_H - 0.2])
+                    hex_pocket(M3_NUT_W + 0.3, M3_NUT_H + 0.3);
+            }
+
+        // Weight relief
+        translate([15, 8, -EPS])
+            cube([BKT_L - 30, BKT_W - 16, BKT_T/2]);
+    }
+}
+
+// ── Part 3: channel_clip ────────────────────────────────────
+// Snap-in clip that locks into divider-wall snap sockets;
+// holds individual bundles in their zone and acts as colour-coded zone marker.
+module channel_clip() {
+    clip_body_w = 6.0;
+    clip_body_h = DIV_T + 4.0;
+    clip_body_t = 8.0;
+    tab_h = 3.5;
+    tab_w = 2.5;
+
+    difference() {
+        union() {
+            // Body spanning divider
+            cube([clip_body_t, clip_body_w, clip_body_h]);
+
+            // Snap tabs (bottom, straddle divider)
+            for (s = [0, clip_body_w - tab_w])
+                translate([clip_body_t/2 - 1, s, -tab_h])
+                    cube([2, tab_w, tab_h + 1]);
+        }
+
+        // Cable radius slot on each face
+        translate([-EPS, clip_body_w/2, clip_body_h * 0.6])
+            rotate([0, 90, 0])
+                cylinder(d=5.0, h=clip_body_t + 2*EPS);
+
+        // Snap tab undercut for flex
+        for (s = [0, clip_body_w - tab_w])
+            translate([clip_body_t/2 - 2, s - EPS, -tab_h + 1.5])
+                cube([4, tab_w + 2*EPS, 1.5]);
+    }
+}
+
+// ── Part 4: cover_panel ─────────────────────────────────────
+// Flat snap-on lid with living-hinge along one long edge.
+// Print flat; PETG living hinge flexes ~90° to snap onto tray.
+module cover_panel() {
+    total_w = TRAY_W + 2 * SNAP_HOOK_T;
+
+    difference() {
+        union() {
+            // Main panel
+            cube([TRAY_L, TRAY_W, CVR_T]);
+
+            // Living hinge strip along back edge (thin, flexes)
+            translate([0, TRAY_W - EPS, 0])
+                cube([TRAY_L, HINGE_W, HINGE_T]);
+
+            // Snap hooks along front edge (clips under tray snap ledge)
+            for (x = [20, TRAY_L/2 - 20, TRAY_L/2 + 20, TRAY_L - 20])
+                translate([x - SNAP_HOOK_T/2, -SNAP_HOOK_H + EPS, 0])
+                    difference() {
+                        cube([SNAP_HOOK_T, SNAP_HOOK_H, CVR_T + 1.5]);
+                        // Hook nose chamfer
+                        translate([-EPS, -EPS, CVR_T])
+                            rotate([0, 0, 0])
+                                cube([SNAP_HOOK_T + 2*EPS, 1.5, 1.5]);
+                    }
+        }
+
+        // Ventilation slots (3 rows × 6 slots)
+        for (row = [0:2])
+            for (col = [0:5]) {
+                sx = 20 + col * 40 + row * 10;
+                sy = 10 + row * 12;
+                if (sx + 25 < TRAY_L && sy + 6 < TRAY_W)
+                    translate([sx, sy, -EPS])
+                        cube([25, 6, CVR_T + 2*EPS]);
+            }
+
+        // Zone label windows (align with tray label slots)
+        zone_ctrs = [TRAY_WALL + ZONE_A_W/2,
+                     TRAY_WALL + ZONE_A_W + DIV_T + ZONE_B_W/2,
+                     TRAY_WALL + ZONE_A_W + DIV_T + ZONE_B_W + DIV_T + ZONE_C_W/2];
+        for (yc = zone_ctrs)
+            translate([TRAY_L/2 - LABEL_W/2, yc - LABEL_H/2, -EPS])
+                cube([LABEL_W, LABEL_H, CVR_T + 2*EPS]);
+    }
+}
+
+// ── Part 5: cable_saddle ────────────────────────────────────
+// Snap-in cable saddle / strain-relief clip; press-fits onto tray top edge.
+module cable_saddle() {
+    arm_gap = TRAY_WALL + 0.4;  // fits over tray wall
+    arm_len = 8.0;
+
+    difference() {
+        union() {
+            // Body
+            chamfer_cube([SAD_W, SAD_T * 2 + arm_gap, SAD_H], ch=1.0);
+
+            // Cable retaining arch
+            translate([SAD_W/2, SAD_T + arm_gap/2, SAD_H])
+                scale([1, 0.6, 1])
+                    difference() {
+                        cylinder(d=SAD_BORE_D + SAD_CLIP_T * 2, h=SAD_T);
+                        translate([0, 0, -EPS])
+                            cylinder(d=SAD_BORE_D, h=SAD_T + 2*EPS);
+                        translate([-SAD_BORE_D, 0, -EPS])
+                            cube([SAD_BORE_D * 2, SAD_BORE_D, SAD_T + 2*EPS]);
+                    }
+        }
+
+        // Slot for tray wall (negative)
+        translate([0, SAD_T, -EPS])
+            cube([SAD_W, arm_gap, arm_len + EPS]);
+
+        // M3 tie-down hole
+        translate([SAD_W/2, SAD_T + arm_gap/2, -EPS])
+            cylinder(d=M3_D, h=SAD_H + 2*EPS);
+    }
+}
+
+// ── Assembly ────────────────────────────────────────────────
+module assembly() {
+    // Tray body (open face up for visibility)
+    color("SteelBlue")
+        tray_body();
+
+    // Two T-nut brackets underneath at 1/4 and 3/4 length
+    for (bx = [TRAY_L/4 - BKT_L/2, 3*TRAY_L/4 - BKT_L/2])
+        color("DodgerBlue")
+            translate([bx, 0, -BKT_T])
+                tnut_bracket();
+
+    // Channel clips (3 per divider position, every 80 mm)
+    for (i = [0:2]) {
+        cx = 40 + i * 80;
+        // Divider A/B
+        color("Tomato", 0.8)
+            translate([cx - 4, TRAY_WALL + ZONE_A_W - 2, TRAY_DEPTH - 3])
+                channel_clip();
+        // Divider B/C
+        color("Orange", 0.8)
+            translate([cx - 4,
+                       TRAY_WALL + ZONE_A_W + DIV_T + ZONE_B_W - 2,
+                       TRAY_DEPTH - 3])
+                channel_clip();
+    }
+
+    // Cover panel (raised above tray to show interior)
+    color("LightSteelBlue", 0.5)
+        translate([0, 0, TRAY_DEPTH + SNAP_LEDGE_H + 4])
+            cover_panel();
+
+    // Cable saddles along front tray edge
+    for (x = [40, 120, 200])
+        color("SlateGray")
+            translate([x - SAD_W/2, -SAD_T * 2 - TRAY_WALL, 0])
+                cable_saddle();
+}
+
+// ── Dispatch ────────────────────────────────────────────────
+if      (RENDER == "tray_body")    tray_body();
+else if (RENDER == "tnut_bracket") tnut_bracket();
+else if (RENDER == "channel_clip") channel_clip();
+else if (RENDER == "cover_panel")  cover_panel();
+else if (RENDER == "cable_saddle") cable_saddle();
+else                               assembly();

chassis/canable_mount.scad

@@ -0,0 +1,265 @@
+// ============================================================
+// canable_mount.scad — CANable 2.0 USB-CAN Adapter Cradle
+// Issue #654 / sl-mechanical  2026-03-16
+// ============================================================
+// Snap-fit cradle for CANable 2.0 PCB (~60 × 18 × 10 mm).
+// Attaches to 2020 aluminium T-slot rail via 2× M5 T-nuts.
+//
+// Port access:
+//   USB-C port       — X− end wall cutout (connector protrudes through)
+//   CAN terminal     — X+ end wall cutout (CANH / CANL / GND wire exit)
+//   LED status window— slot in Y+ side wall, PCB top-face LEDs visible
+//
+// Retention: snap-fit cantilever lips on both side walls (PETG flex).
+// Cable strain relief: zip-tie boss pair on X+ shelf (CAN wires).
+//
+// ⚠  VERIFY WITH CALIPERS BEFORE PRINTING:
+//    PCB_L, PCB_W          board outline
+//    USBC_W, USBC_H        USB-C shell at X− edge
+//    TERM_W, TERM_H        3-pos terminal block at X+ edge
+//    LED_X_CTR, LED_WIN_W  LED window position on Y+ wall
+//
+// Print settings (PETG):
+//   3 perimeters, 40 % gyroid infill, no supports, 0.2 mm layer
+//   Print orientation: open face UP (as modelled)
+//
+// BOM:
+//   2 × M5×10 BHCS  +  2 × M5 slide-in T-nut  (2020 rail)
+//
+// Export commands:
+//   openscad -D 'RENDER="mount"'    -o canable_mount.stl    canable_mount.scad
+//   openscad -D 'RENDER="assembly"' -o canable_assembly.png canable_mount.scad
+// ============================================================
+
+RENDER = "assembly"; // mount | assembly
+
+$fn = 48;
+EPS = 0.01;
+
+// ── ⚠ Verify before printing ─────────────────────────────────
+// CANable 2.0 PCB
+PCB_L    = 60.0;   // board length  (X: USB-C end → terminal end)
+PCB_W    = 18.0;   // board width   (Y)
+PCB_T    =  1.6;   // board thickness
+COMP_H   =  8.5;   // tallest component above board (USB-C shell ≈ 3.5 mm;
+                   //   terminal block ≈ 8.5 mm)
+
+// USB-C connector (at X− end face of PCB)
+USBC_W   =  9.5;   // connector outer width
+USBC_H   =  3.8;   // connector outer height above board surface
+USBC_Z0  =  0.0;   // connector bottom offset above board surface
+
+// CAN screw-terminal block (at X+ end face, 3-pos 5.0 mm pitch)
+TERM_W   = 16.0;   // terminal block span (3 × 5 mm + housing)
+TERM_H   =  9.0;   // terminal block height above board surface
+TERM_Z0  =  0.5;   // terminal bottom offset above board surface
+
+// Status LED window (LEDs near USB-C end on PCB top face)
+//   Rectangular slot cut in Y+ side wall — LEDs visible from the side
+LED_X_CTR  = 11.0;  // LED zone centre measured from PCB X− edge
+LED_WIN_W  = 14.0;  // window width (X)
+LED_WIN_H  =  5.5;  // window height (Z) — opens top portion of side wall
+
+// ── Cradle geometry ──────────────────────────────────────────
+WALL_T   = 2.5;    // side/end wall thickness
+FLOOR_T  = 4.0;    // floor plate thickness (accommodates M5 BHCS head pocket)
+CL_SIDE  = 0.30;   // Y clearance per side (total 0.6 mm play)
+CL_END   = 0.40;   // X clearance per end
+
+// Interior cavity
+INN_W    = PCB_W + 2*CL_SIDE;          // Y span
+INN_L    = PCB_L + 2*CL_END;           // X span
+INN_H    = PCB_T + COMP_H + 1.2;       // Z height (board + tallest comp + margin)
+
+// Outer body
+OTR_W    = INN_W  + 2*WALL_T;          // Y
+OTR_L    = INN_L  + 2*WALL_T;          // X
+OTR_H    = FLOOR_T + INN_H;            // Z
+
+// PCB reference origin within body (lower-left corner of board)
+PCB_X0   = WALL_T + CL_END;            // board X start inside body
+PCB_Y0   = WALL_T + CL_SIDE;           // board Y start inside body
+PCB_Z0   = FLOOR_T;                    // board bottom sits on floor
+
+// ── Snap-fit lips ─────────────────────────────────────────────
+// Cantilever ledge on inner face of each side wall, at PCB-top Z.
+// Tapered (chamfered) entry guides PCB in from above.
+SNAP_IN  = 0.8;    // how far inward ledge protrudes over PCB edge
+SNAP_T   = 1.2;    // snap-arm thickness (thin for PETG flex)
+SNAP_H   = 4.0;    // cantilever arm height (root at OTR_H, tip near PCB_Z0+PCB_T)
+SNAP_L   = 18.0;   // arm length along X (centred on PCB, shorter = more flex)
+// Snap on Y− wall protrudes in +Y direction; Y+ wall protrudes in −Y direction
+
+// ── M5 T-nut mount (2020 rail) ────────────────────────────────
+M5_D       =  5.3;   // M5 bolt clearance bore
+M5_HEAD_D  =  9.5;   // M5 BHCS head pocket diameter (from bottom face)
+M5_HEAD_H  =  3.0;   // BHCS head pocket depth
+M5_SPAC    = 20.0;   // bolt spacing along X (centred on cradle)
+// Standard M5 slide-in T-nuts used — no T-nut pocket moulded in.
+
+// ── Cable strain relief ───────────────────────────────────────
+// Two zip-tie anchor bosses on a shelf inside the X+ end, straddling
+// the CAN terminal wires.
+SR_BOSS_OD =  7.0;   // boss outer diameter
+SR_BOSS_H  =  5.5;   // boss height above floor
+SR_SLOT_W  =  3.5;   // zip-tie slot width
+SR_SLOT_T  =  2.2;   // zip-tie slot through-height
+// Boss Y positions (straddle terminal block)
+SR_Y1      = WALL_T + INN_W * 0.25;
+SR_Y2      = WALL_T + INN_W * 0.75;
+SR_X       = OTR_L - WALL_T - SR_BOSS_OD/2 - 2.5;  // just inside X+ end wall
+
+// ─────────────────────────────────────────────────────────────
+module canable_mount() {
+    difference() {
+        // ── Outer solid body ──────────────────────────────────
+        union() {
+            cube([OTR_L, OTR_W, OTR_H]);
+
+            // ── Snap cantilever arms on Y− wall (protrude inward +Y) ──
+            // Arms hang down from top of Y− wall inner face.
+            // Root is flush with inner face (Y = WALL_T); tip at PCB level.
+            translate([OTR_L/2 - SNAP_L/2, WALL_T - SNAP_T, OTR_H - SNAP_H])
+                cube([SNAP_L, SNAP_T, SNAP_H]);
+
+            // ── Snap cantilever arms on Y+ wall (protrude inward −Y) ──
+            translate([OTR_L/2 - SNAP_L/2, OTR_W - WALL_T, OTR_H - SNAP_H])
+                cube([SNAP_L, SNAP_T, SNAP_H]);
+
+            // ── Cable strain relief bosses (X+ end, inside) ────
+            for (sy = [SR_Y1, SR_Y2])
+                translate([SR_X, sy, 0])
+                    cylinder(d=SR_BOSS_OD, h=SR_BOSS_H);
+        }
+
+        // ── Interior cavity ───────────────────────────────────
+        translate([WALL_T, WALL_T, FLOOR_T])
+            cube([INN_L, INN_W, INN_H + EPS]);
+
+        // ── USB-C cutout — X− end wall ────────────────────────
+        // Centred on PCB width; opened from board surface upward
+        translate([-EPS,
+                   PCB_Y0 + PCB_W/2 - (USBC_W + 1.5)/2,
+                   PCB_Z0 + USBC_Z0 - 0.5])
+            cube([WALL_T + 2*EPS, USBC_W + 1.5, USBC_H + 2.5]);
+
+        // ── CAN terminal cutout — X+ end wall ─────────────────
+        // Full terminal width + 2 mm margin for screwdriver access;
+        // height clears terminal block + wire bend radius
+        translate([OTR_L - WALL_T - EPS,
+                   PCB_Y0 + PCB_W/2 - (TERM_W + 2.0)/2,
+                   PCB_Z0 + TERM_Z0 - 0.5])
+            cube([WALL_T + 2*EPS, TERM_W + 2.0, TERM_H + 5.0]);
+
+        // ── LED status window — Y+ side wall ─────────────────
+        // Rectangular slot; LEDs at top-face of PCB are visible through it
+        translate([PCB_X0 + LED_X_CTR - LED_WIN_W/2,
+                   OTR_W - WALL_T - EPS,
+                   OTR_H - LED_WIN_H])
+            cube([LED_WIN_W, WALL_T + 2*EPS, LED_WIN_H + EPS]);
+
+        // ── M5 BHCS head pockets (from bottom face of floor) ──
+        for (mx = [OTR_L/2 - M5_SPAC/2, OTR_L/2 + M5_SPAC/2])
+            translate([mx, OTR_W/2, -EPS]) {
+                // Clearance bore through full floor
+                cylinder(d=M5_D, h=FLOOR_T + 2*EPS);
+                // BHCS head pocket from bottom face
+                cylinder(d=M5_HEAD_D, h=M5_HEAD_H + EPS);
+            }
+
+        // ── Snap-arm ledge slot — Y− arm (hollow out to thin arm) ──
+        // Arm is SNAP_T thick; cut away material behind arm
+        translate([OTR_L/2 - SNAP_L/2 - EPS, EPS, OTR_H - SNAP_H])
+            cube([SNAP_L + 2*EPS, WALL_T - SNAP_T - EPS, SNAP_H + EPS]);
+
+        // ── Snap-arm ledge slot — Y+ arm ──────────────────────
+        translate([OTR_L/2 - SNAP_L/2 - EPS, OTR_W - WALL_T + SNAP_T, OTR_H - SNAP_H])
+            cube([SNAP_L + 2*EPS, WALL_T - SNAP_T - EPS, SNAP_H + EPS]);
+
+        // ── Snap-arm inward ledge notch (entry chamfer removed) ─
+        // Chamfer top of snap arm so PCB slides in easily
+        // Y− arm: chamfer on upper-inner edge → 45° wedge on +Y/+Z corner
+        translate([OTR_L/2 - SNAP_L/2 - EPS,
+                   WALL_T - SNAP_T - EPS,
+                   OTR_H - SNAP_IN])
+            rotate([0, 0, 0])
+            rotate([45, 0, 0])
+                cube([SNAP_L + 2*EPS, SNAP_IN * 1.5, SNAP_IN * 1.5]);
+
+        // Y+ arm: chamfer on upper-inner edge
+        translate([OTR_L/2 - SNAP_L/2 - EPS,
+                   OTR_W - WALL_T + SNAP_T - SNAP_IN * 1.5 + EPS,
+                   OTR_H - SNAP_IN])
+            rotate([45, 0, 0])
+                cube([SNAP_L + 2*EPS, SNAP_IN * 1.5, SNAP_IN * 1.5]);
+
+        // ── Snap ledge cutout on Y− arm inner tip ─────────────
+        // Creates inward nub: remove top portion of arm inner tip
+        // leaving bottom SNAP_IN height as the retaining ledge
+        translate([OTR_L/2 - SNAP_L/2 - EPS,
+                   WALL_T - SNAP_T - EPS,
+                   PCB_Z0 + PCB_T + SNAP_IN])
+            cube([SNAP_L + 2*EPS, SNAP_T + 2*EPS,
+                  OTR_H - (PCB_Z0 + PCB_T + SNAP_IN) + EPS]);
+
+        // ── Snap ledge cutout on Y+ arm inner tip ─────────────
+        translate([OTR_L/2 - SNAP_L/2 - EPS,
+                   OTR_W - WALL_T - EPS,
+                   PCB_Z0 + PCB_T + SNAP_IN])
+            cube([SNAP_L + 2*EPS, SNAP_T + 2*EPS,
+                  OTR_H - (PCB_Z0 + PCB_T + SNAP_IN) + EPS]);
+
+        // ── Zip-tie slots through strain relief bosses ─────────
+        for (sy = [SR_Y1, SR_Y2])
+            translate([SR_X, sy,
+                       SR_BOSS_H/2 - SR_SLOT_T/2])
+                rotate([0, 90, 0])
+                    cube([SR_SLOT_T, SR_SLOT_W,
+                          SR_BOSS_OD + 2*EPS],
+                         center=true);
+
+        // ── Weight relief pocket in floor (underside) ─────────
+        translate([WALL_T + 8, WALL_T + 3, -EPS])
+            cube([OTR_L - 2*WALL_T - 16, OTR_W - 2*WALL_T - 6,
+                  FLOOR_T - 1.5 + EPS]);
+    }
+}
+
+// ── Assembly preview ─────────────────────────────────────────
+if (RENDER == "assembly") {
+    color("DimGray", 0.93) canable_mount();
+
+    // Phantom PCB
+    color("MidnightBlue", 0.35)
+        translate([PCB_X0, PCB_Y0, PCB_Z0])
+            cube([PCB_L, PCB_W, PCB_T]);
+
+    // Phantom component block (top of PCB)
+    color("DarkSlateGray", 0.25)
+        translate([PCB_X0, PCB_Y0, PCB_Z0 + PCB_T])
+            cube([PCB_L, PCB_W, COMP_H]);
+
+    // USB-C port highlight
+    color("Gold", 0.8)
+        translate([-1,
+                   PCB_Y0 + PCB_W/2 - USBC_W/2,
+                   PCB_Z0 + USBC_Z0])
+            cube([WALL_T + 2, USBC_W, USBC_H]);
+
+    // Terminal block highlight
+    color("Tomato", 0.7)
+        translate([OTR_L - WALL_T - 1,
+                   PCB_Y0 + PCB_W/2 - TERM_W/2,
+                   PCB_Z0 + TERM_Z0])
+            cube([WALL_T + 2, TERM_W, TERM_H]);
+
+    // LED zone highlight
+    color("LimeGreen", 0.9)
+        translate([PCB_X0 + LED_X_CTR - LED_WIN_W/2,
+                   OTR_W - WALL_T - 0.5,
+                   OTR_H - LED_WIN_H + 1])
+            cube([LED_WIN_W, 1, LED_WIN_H - 2]);
+
+} else {
+    canable_mount();
+}

chassis/chassis_frame.scad

@@ -8,9 +8,9 @@
 // Requirements:
 //   - 600mm wheelbase
 //   - 2x hoverboard hub motors (170mm OD)
-//   - STM32 MAMBA F722S FC mount (30.5x30.5mm pattern)
+//   - ESP32-S3 ESP32-S3 BALANCE FC mount (30.5x30.5mm pattern)
 //   - Battery tray (24V 4Ah — ~180x70x50mm pack)
-//   - Jetson Nano B01 mount plate (100x80mm, M3 holes)
+//   - Jetson Orin Nano Super B01 mount plate (100x80mm, M3 holes)
 //   - Front/rear bumper brackets
 // =============================================================================
 
@@ -37,7 +37,7 @@ MOTOR_FORK_H       = 80;    // mm, total height of motor fork bracket
 MOTOR_FORK_T       = 8;     // mm, fork plate thickness
 AXLE_HEIGHT        = 310;   // mm, axle CL above ground (motor radius + clearance)
 
-// ── FC mount (MAMBA F722S — 30.5 × 30.5 mm M3 pattern) ──────────────────────
+// ── FC mount (ESP32-S3 BALANCE — 30.5 × 30.5 mm M3 pattern) ──────────────────────
 FC_MOUNT_SPACING   = 30.5;  // mm, hole pattern pitch
 FC_MOUNT_HOLE_D    = 3.2;   // mm, M3 clearance
 FC_STANDOFF_H      = 6;     // mm, standoff height
@@ -52,7 +52,7 @@ BATT_FLOOR         = 4;     // mm, tray floor thickness
 BATT_STRAP_W       = 20;    // mm, Velcro strap slot width
 BATT_STRAP_T       = 2;     // mm, strap slot depth
 
-// ── Jetson Nano B01 mount plate ──────────────────────────────────────────────
+// ── Jetson Orin Nano Super B01 mount plate ──────────────────────────────────────────────
 // B01 carrier board hole pattern: 58 x 58 mm M3 (inner) + corner pass-throughs
 JETSON_HOLE_PITCH  = 58;    // mm, M3 mounting hole pattern
 JETSON_HOLE_D      = 3.2;   // mm
@@ -210,7 +210,7 @@ module battery_tray() {
 
 // ─── FC mount holes helper ────────────────────────────────────────────────────
 module fc_mount_holes(z_offset=0, depth=10) {
-    // MAMBA F722S: 30.5×30.5 mm M3 pattern, centred at origin
+    // ESP32-S3 BALANCE: 30.5×30.5 mm M3 pattern, centred at origin
     for (x = [-FC_MOUNT_SPACING/2, FC_MOUNT_SPACING/2])
     for (y = [-FC_MOUNT_SPACING/2, FC_MOUNT_SPACING/2])
         translate([x, y, z_offset])
@@ -247,7 +247,7 @@ module fc_mount_plate() {
     }
 }
 
-// ─── Jetson Nano B01 mount plate ─────────────────────────────────────────────
+// ─── Jetson Orin Nano Super B01 mount plate ─────────────────────────────────────────────
 // Positioned rear of deck, elevated on standoffs
 module jetson_mount_plate() {
     jet_x =  60;   // offset toward rear

chassis/gimbal_camera_mount.scad

@@ -0,0 +1,599 @@
+// ============================================================
+// gimbal_camera_mount.scad — Pan/Tilt Gimbal Mount for RealSense D435i
+// Issue: #552  Agent: sl-mechanical  Date: 2026-03-14
+// ============================================================
+//
+// Parametric gimbal bracket system mounting an Intel RealSense D435i
+// (or similar box camera) on a 2-axis pan/tilt gimbal driven by
+// ST3215 serial bus servos (25T spline, Feetech/Waveshare).
+//
+// Architecture:
+//   Pan axis  — base T-nut clamps to 2020 rail; pan servo rotates yoke
+//   Tilt axis — tilt servo horn plate bolts to ST3215 horn; camera cradle
+//               rocks on tilt axis
+//   Camera    — D435i captured via 1/4-20 UNC hex nut in cradle floor
+//   Damping   — PETG flexure ribs on camera contact faces (or TPU pads)
+//   Wiring    — USB-C cable routed through channel in cradle arm
+//
+// Part catalogue:
+//   Part 1 — tnut_rail_base()       2020 rail T-nut base + pan servo seat
+//   Part 2 — pan_yoke()             U-yoke connecting pan servo to tilt axis
+//   Part 3 — tilt_horn_plate()      Plate bolting to ST3215 tilt servo horn
+//   Part 4 — camera_cradle()        D435i cradle with 1/4-20 captured nut
+//   Part 5 — vibe_pad()             PETG flexure vibration-damping pad (×2)
+//   Part 6 — assembly_preview()     Full assembly preview
+//
+// Hardware BOM (per gimbal):
+//   2× ST3215 serial bus servo (pan + tilt)
+//   2× servo horn (25T spline, ≥Ø36 mm, 4× M3 bolt holes on Ø24 mm BC)
+//   2× M3 × 8 mm SHCS          horn-to-plate bolts (×4 each horn = 8 total)
+//   1× M3 × 16 mm SHCS + nut   T-nut rail clamp thumbscrew
+//   1× 1/4-20 UNC × 8 mm SHCS  camera retention bolt (or existing tripod screw)
+//   1× 1/4-20 UNC hex nut       captured in cradle floor
+//   4× M3 × 12 mm SHCS          yoke-to-tilt-plate pivot axle bolts
+//   2× M3 × 25 mm SHCS          pan yoke attachment to servo body
+//   (optional) 2× vibe_pad printed in TPU 95A
+//
+// ST3215 servo interface (caliper-verified Feetech ST3215):
+//   Body footprint : 40.0 × 20.0 mm (W × D), 36.5 mm tall
+//   Shaft centre H : 28.5 mm from mounting face
+//   Shaft spline   : 25T, centre Ø5.8 mm, D-cut
+//   Mount holes    : 4× M3 on 32 × 10 mm rectangular pattern (18 mm offset)
+//   Horn bolt circle: Ø24 mm, 4× M3
+//   Horn OD        : ~36 mm
+//
+// D435i camera interface (caliper-verified):
+//   Body           : 90 × 25 × 25 mm (W × D × H)
+//   Tripod thread  : 1/4-20 UNC, centred bottom face, 9 mm from front
+//   USB-C connector: right rear, 8 × 5 mm opening, 4 mm from edge
+//
+// Parametric camera size (override to adapt to other cameras):
+//   CAM_W, CAM_D, CAM_H  — body envelope
+//   CAM_MOUNT_X           — tripod hole X offset from camera centre
+//   CAM_MOUNT_Y           — tripod hole Y offset from front face
+//
+// Coordinate convention:
+//   Camera looks in +Y direction (forward)
+//   Pan axis is Z (vertical); tilt axis is X (lateral)
+//   Rail runs along Z; T-nut base at Z=0
+//   All parts at assembly origin; translate for assembly_preview
+//
+// RENDER options:
+//   "assembly"            full assembly preview (default)
+//   "tnut_rail_base_stl"  Part 1
+//   "pan_yoke_stl"        Part 2
+//   "tilt_horn_plate_stl" Part 3
+//   "camera_cradle_stl"   Part 4
+//   "vibe_pad_stl"        Part 5
+//
+// Export commands:
+//   openscad gimbal_camera_mount.scad -D 'RENDER="tnut_rail_base_stl"'  -o gcm_tnut_base.stl
+//   openscad gimbal_camera_mount.scad -D 'RENDER="pan_yoke_stl"'        -o gcm_pan_yoke.stl
+//   openscad gimbal_camera_mount.scad -D 'RENDER="tilt_horn_plate_stl"' -o gcm_tilt_horn_plate.stl
+//   openscad gimbal_camera_mount.scad -D 'RENDER="camera_cradle_stl"'   -o gcm_camera_cradle.stl
+//   openscad gimbal_camera_mount.scad -D 'RENDER="vibe_pad_stl"'        -o gcm_vibe_pad.stl
+// ============================================================
+
+$fn = 64;
+e   = 0.01;   // epsilon for boolean clearance
+
+// ── Parametric camera envelope ────────────────────────────────────────────────
+// Override these for cameras other than D435i
+CAM_W          = 90.0;   // camera body width (X)
+CAM_D          = 25.0;   // camera body depth (Y)
+CAM_H          = 25.0;   // camera body height (Z)
+CAM_MOUNT_X    =  0.0;   // tripod hole X offset from camera body centre
+CAM_MOUNT_Y    =  9.0;   // tripod hole from front face (Y)  [D435i: 9 mm]
+CAM_USBC_X     = CAM_W/2 - 4;   // USB-C connector X (right side)
+CAM_USBC_Z     = CAM_H/2;       // USB-C connector Z (mid-height rear)
+CAM_USBC_W     =  9.0;   // USB-C opening width (X)
+CAM_USBC_H     =  5.0;   // USB-C opening height (Z)
+
+// ── Rail geometry (matches sensor_rail.scad / sensor_rail_brackets.scad) ─────
+RAIL_W         = 20.0;
+SLOT_OPEN      =  6.0;
+SLOT_INNER_W   = 10.2;
+SLOT_INNER_H   =  5.8;
+SLOT_NECK_H    =  3.2;
+
+// ── T-nut geometry (matches sensor_rail_brackets.scad) ───────────────────────
+TNUT_W         =  9.8;
+TNUT_H         =  5.5;
+TNUT_L         = 12.0;
+TNUT_M3_NUT_AF =  5.5;
+TNUT_M3_NUT_H  =  2.5;
+TNUT_BOLT_D    =  3.3;   // M3 clearance
+
+// ── T-nut base plate geometry ─────────────────────────────────────────────────
+BASE_W         = 44.0;   // wide enough for pan servo body (40 mm)
+BASE_H         = 40.0;   // height along rail (Z)
+BASE_T         = SLOT_NECK_H + 2.0;   // plate depth (Y), rail-face side
+
+// ── ST3215 servo geometry ─────────────────────────────────────────────────────
+SERVO_W        = 40.0;   // servo body width (X)
+SERVO_D        = 20.0;   // servo body depth (Y)
+SERVO_H        = 36.5;   // servo body height (Z)
+SERVO_SHAFT_Z  = 28.5;   // shaft centre height from mounting face
+SERVO_HOLE_X   = 16.0;   // mount hole half-span X (32 mm span)
+SERVO_HOLE_Y   =  5.0;   // mount hole half-span Y (10 mm span)
+SERVO_M3_D     =  3.3;   // M3 clearance
+
+// ── Servo horn geometry ───────────────────────────────────────────────────────
+HORN_OD        = 36.0;   // horn outer diameter
+HORN_SPLINE_D  =  5.9;   // 25T spline bore clearance (5.8 + 0.1)
+HORN_BC_D      = 24.0;   // bolt circle diameter (4× M3)
+HORN_BOLT_D    =  3.3;   // M3 clearance through horn plate
+HORN_PLATE_T   =  5.0;   // tilt horn plate thickness
+
+// ── Yoke geometry ─────────────────────────────────────────────────────────────
+YOKE_WALL_T    =  5.0;   // yoke arm wall thickness
+YOKE_ARM_H     = 50.0;   // yoke arm height (Z) — clears servo body + camera
+YOKE_INNER_W   = CAM_W + 8.0;  // yoke inner span (camera + pad clearance)
+YOKE_BASE_T    =  8.0;   // yoke base plate thickness
+
+// ── Tilt pivot ────────────────────────────────────────────────────────────────
+PIVOT_D        =  4.3;   // M4 pivot axle bore
+PIVOT_BOSS_D   = 10.0;   // boss OD around pivot bore
+PIVOT_BOSS_L   =  6.0;   // boss protrusion from yoke wall
+
+// ── Camera cradle geometry ────────────────────────────────────────────────────
+CRADLE_WALL_T  =  4.0;   // cradle side wall thickness
+CRADLE_FLOOR_T =  5.0;   // cradle floor thickness (holds 1/4-20 nut)
+CRADLE_LIP_T   =  3.0;   // front retaining lip thickness
+CRADLE_LIP_H   =  8.0;   // front lip height
+CABLE_CH_W     = 12.0;   // USB-C cable channel width
+CABLE_CH_H     =  8.0;   // USB-C cable channel height
+
+// ── 1/4-20 UNC tripod thread ──────────────────────────────────────────────────
+QTR20_D        =  6.6;   // 1/4-20 clearance bore
+QTR20_NUT_AF   = 11.1;   // 1/4-20 hex nut across-flats (standard)
+QTR20_NUT_H    =  5.5;   // 1/4-20 hex nut height
+
+// ── Vibration-damping pad geometry ────────────────────────────────────────────
+PAD_W          = CAM_W - 2*CRADLE_WALL_T - 2;
+PAD_H          = CAM_H + 4;
+PAD_T          =  2.5;   // pad body thickness
+RIB_H          =  1.5;   // flexure rib height
+RIB_W          =  1.2;   // rib width
+RIB_PITCH      =  5.0;   // rib pitch
+
+// ── Fastener sizes ────────────────────────────────────────────────────────────
+M3_D = 3.3;
+M4_D = 4.3;
+M3_NUT_AF = 5.5;
+M3_NUT_H  = 2.4;
+
+// ============================================================
+// RENDER DISPATCH
+// ============================================================
+RENDER = "assembly";
+
+if      (RENDER == "assembly")            assembly_preview();
+else if (RENDER == "tnut_rail_base_stl")  tnut_rail_base();
+else if (RENDER == "pan_yoke_stl")        pan_yoke();
+else if (RENDER == "tilt_horn_plate_stl") tilt_horn_plate();
+else if (RENDER == "camera_cradle_stl")   camera_cradle();
+else if (RENDER == "vibe_pad_stl")        vibe_pad();
+
+// ============================================================
+// ASSEMBLY PREVIEW
+// ============================================================
+module assembly_preview() {
+    asm_rail_z = 0;
+    // Rail section ghost (200 mm)
+    %color("Silver", 0.25)
+        translate([-RAIL_W/2, -RAIL_W/2, asm_rail_z])
+            cube([RAIL_W, RAIL_W, 200]);
+
+    // T-nut rail base
+    color("OliveDrab", 0.85)
+        translate([0, 0, asm_rail_z + 80])
+            tnut_rail_base();
+
+    // Pan servo ghost (sitting in base seat)
+    %color("DimGray", 0.4)
+        translate([-SERVO_W/2, BASE_T, asm_rail_z + 80 + (BASE_H - SERVO_H)/2])
+            cube([SERVO_W, SERVO_D, SERVO_H]);
+
+    // Pan yoke rising from servo shaft
+    color("SteelBlue", 0.85)
+        translate([0, BASE_T + SERVO_D, asm_rail_z + 80 + BASE_H/2])
+            pan_yoke();
+
+    // Tilt horn plate (tilt axis — left yoke wall)
+    color("DarkOrange", 0.85)
+        translate([-YOKE_INNER_W/2 - YOKE_WALL_T - HORN_PLATE_T,
+                   BASE_T + SERVO_D + YOKE_BASE_T,
+                   asm_rail_z + 80 + BASE_H/2 + YOKE_ARM_H/2])
+            rotate([0, 90, 0])
+                tilt_horn_plate();
+
+    // Camera cradle (centred in yoke)
+    color("DarkSlateGray", 0.85)
+        translate([0, BASE_T + SERVO_D + YOKE_BASE_T + CRADLE_FLOOR_T,
+                   asm_rail_z + 80 + BASE_H/2 + YOKE_ARM_H/2 - CAM_H/2])
+            camera_cradle();
+
+    // D435i ghost
+    %color("Black", 0.4)
+        translate([-CAM_W/2,
+                   BASE_T + SERVO_D + YOKE_BASE_T + CRADLE_FLOOR_T + PAD_T,
+                   asm_rail_z + 80 + Base_H_mid() - CAM_H/2])
+            cube([CAM_W, CAM_D, CAM_H]);
+
+    // Vibe pads (front + rear camera face)
+    color("DimGray", 0.80) {
+        translate([-CAM_W/2 + CRADLE_WALL_T + 1,
+                   Base_T + SERVO_D + YOKE_BASE_T + CRADLE_FLOOR_T,
+                   asm_rail_z + 80 + Base_H_mid() - PAD_H/2])
+            rotate([90, 0, 0])
+                vibe_pad();
+    }
+}
+
+// helper (avoids recomputing same expression)
+function Base_T() = BASE_T;
+function Base_H_mid() = BASE_H/2 + YOKE_ARM_H/2;
+
+// ============================================================
+// PART 1 — T-NUT RAIL BASE  (pan servo seat + rail clamp)
+// ============================================================
+// Mounts to 2020 rail via standard T-nut tongue.
+// Front face (+Y side) provides flat seat for pan ST3215 servo body.
+// Servo body recessed 1 mm into seat for positive lateral registration.
+// Pan servo shaft axis = Z (vertical) → pan rotation about Z.
+//
+// Print: PETG, 5 perims, 50 % gyroid. Orient face-plate down (flat).
+module tnut_rail_base() {
+    difference() {
+        union() {
+            // ── Face plate (against rail outer face, -Y side) ────────────
+            translate([-BASE_W/2, -BASE_T, 0])
+                cube([BASE_W, BASE_T, BASE_H]);
+
+            // ── T-nut neck (enters rail slot, +Y side of face plate) ─────
+            translate([-TNUT_W/2, 0, (BASE_H - TNUT_L)/2])
+                cube([TNUT_W, SLOT_NECK_H + e, TNUT_L]);
+
+            // ── T-nut inner body (wider, locks inside T-groove) ──────────
+            translate([-TNUT_W/2, SLOT_NECK_H - e, (BASE_H - TNUT_L)/2])
+                cube([TNUT_W, TNUT_H - SLOT_NECK_H + e, TNUT_L]);
+
+            // ── Pan servo seat boss (front face, +Y side) ────────────────
+            // Proud pad that servo body sits on; 1 mm registration recess
+            translate([-BASE_W/2, -BASE_T, 0])
+                cube([BASE_W, BASE_T + 6, BASE_H]);
+        }
+
+        // ── Rail clamp bolt bore (M3 through face plate) ─────────────────
+        translate([0, -BASE_T - e, BASE_H/2])
+            rotate([-90, 0, 0])
+                cylinder(d = TNUT_BOLT_D, h = BASE_T + TNUT_H + 2*e);
+
+        // ── M3 hex nut pocket (inside T-nut body) ────────────────────────
+        translate([0, SLOT_NECK_H + 0.3, BASE_H/2])
+            rotate([-90, 0, 0])
+                cylinder(d = TNUT_M3_NUT_AF / cos(30),
+                         h = TNUT_M3_NUT_H + 0.3, $fn = 6);
+
+        // ── Servo body recess (1 mm registration pocket in seat face) ────
+        translate([-SERVO_W/2 - 0.3, -BASE_T + 6 - 1.0,
+                   (BASE_H - SERVO_H)/2 - 0.3])
+            cube([SERVO_W + 0.6, 1.2, SERVO_H + 0.6]);
+
+        // ── Pan servo mount holes (4× M3 in rectangular pattern) ─────────
+        for (sx = [-SERVO_HOLE_X, SERVO_HOLE_X])
+        for (sy = [-SERVO_HOLE_Y, SERVO_HOLE_Y])
+            translate([sx, -BASE_T + 6 + e, BASE_H/2 + sy])
+                rotate([90, 0, 0])
+                    cylinder(d = SERVO_M3_D, h = BASE_T + 2*e);
+
+        // ── Pan servo shaft bore (passes shaft through base if needed) ────
+        // Centre of shaft at Z = BASE_H/2, no bore needed (shaft exits top)
+
+        // ── Lightening pockets ────────────────────────────────────────────
+        translate([0, -BASE_T/2 + 3, BASE_H/2])
+            cube([BASE_W - 14, BASE_T - 4, BASE_H - 14], center = true);
+    }
+}
+
+// ============================================================
+// PART 2 — PAN YOKE
+// ============================================================
+// U-shaped yoke that attaches to pan servo horn (below) and carries
+// the tilt axis (above).  Two vertical arms straddle the camera cradle.
+// Tilt servo sits on top of one arm; tilt pivot boss on the other.
+//
+// Yoke base bolts to pan servo horn (4× M3 on HORN_BC_D bolt circle).
+// Pan servo horn spline bore passes through yoke base centre.
+// Tilt axis: M4 pivot axle through boss on each arm (X-axis rotation).
+//
+// Print: upright (yoke in final orientation), PETG, 5 perims, 40% gyroid.
+module pan_yoke() {
+    arm_z_total = YOKE_ARM_H + YOKE_BASE_T;
+    inner_w     = YOKE_INNER_W;
+
+    difference() {
+        union() {
+            // ── Yoke base plate (bolts to pan servo horn) ─────────────────
+            translate([-inner_w/2 - YOKE_WALL_T, 0, 0])
+                cube([inner_w + 2*YOKE_WALL_T, YOKE_BASE_T, YOKE_BASE_T]);
+
+            // ── Left arm ──────────────────────────────────────────────────
+            translate([-inner_w/2 - YOKE_WALL_T, 0, 0])
+                cube([YOKE_WALL_T, YOKE_BASE_T, arm_z_total]);
+
+            // ── Right arm (tilt servo side) ───────────────────────────────
+            translate([inner_w/2, 0, 0])
+                cube([YOKE_WALL_T, YOKE_BASE_T, arm_z_total]);
+
+            // ── Tilt pivot bosses (both arms, X-axis) ─────────────────────
+            // Left pivot boss (plain pivot — M4 bolt)
+            translate([-inner_w/2 - YOKE_WALL_T - PIVOT_BOSS_L,
+                       YOKE_BASE_T/2,
+                       YOKE_BASE_T + YOKE_ARM_H/2])
+                rotate([0, 90, 0])
+                    cylinder(d = PIVOT_BOSS_D, h = PIVOT_BOSS_L + YOKE_WALL_T);
+
+            // Right pivot boss (tilt servo horn seat)
+            translate([inner_w/2,
+                       YOKE_BASE_T/2,
+                       YOKE_BASE_T + YOKE_ARM_H/2])
+                rotate([0, 90, 0])
+                    cylinder(d = PIVOT_BOSS_D + 4, h = PIVOT_BOSS_L + YOKE_WALL_T);
+
+            // ── Tilt servo body seat on right arm top ─────────────────────
+            translate([inner_w/2, 0, arm_z_total - SERVO_H - 4])
+                cube([YOKE_WALL_T + SERVO_D + 2, YOKE_BASE_T, SERVO_H + 4]);
+        }
+
+        // ── Pan horn spline bore (centre of yoke base) ────────────────────
+        translate([0, YOKE_BASE_T/2, YOKE_BASE_T/2])
+            rotate([90, 0, 0])
+                cylinder(d = HORN_SPLINE_D, h = YOKE_BASE_T + 2*e,
+                         center = true);
+
+        // ── Pan horn bolt holes (4× M3 on HORN_BC_D) ─────────────────────
+        for (a = [45, 135, 225, 315])
+            translate([HORN_BC_D/2 * cos(a),
+                       YOKE_BASE_T/2,
+                       HORN_BC_D/2 * sin(a) + YOKE_BASE_T/2])
+                rotate([90, 0, 0])
+                    cylinder(d = HORN_BOLT_D, h = YOKE_BASE_T + 2*e,
+                             center = true);
+
+        // ── Left tilt pivot bore (M4 clearance) ───────────────────────────
+        translate([-inner_w/2 - YOKE_WALL_T - PIVOT_BOSS_L - e,
+                   YOKE_BASE_T/2,
+                   YOKE_BASE_T + YOKE_ARM_H/2])
+            rotate([0, 90, 0])
+                cylinder(d = PIVOT_D, h = PIVOT_BOSS_L + YOKE_WALL_T + 2*e);
+
+        // ── Right tilt pivot bore (larger — tilt horn plate seats here) ───
+        translate([inner_w/2 - e,
+                   YOKE_BASE_T/2,
+                   YOKE_BASE_T + YOKE_ARM_H/2])
+            rotate([0, 90, 0])
+                cylinder(d = HORN_SPLINE_D,
+                         h = PIVOT_BOSS_L + YOKE_WALL_T + 2*e);
+
+        // ── Tilt servo mount holes in right arm seat ──────────────────────
+        for (sz = [-SERVO_HOLE_Y, SERVO_HOLE_Y])
+            translate([inner_w/2 + YOKE_WALL_T + SERVO_D/2,
+                       YOKE_BASE_T/2,
+                       arm_z_total - SERVO_H/2 + sz])
+                rotate([90, 0, 0])
+                    cylinder(d = SERVO_M3_D, h = YOKE_BASE_T + 2*e,
+                             center = true);
+
+        // ── M3 nut pockets (tilt servo mount, rear of arm seat) ──────────
+        for (sz = [-SERVO_HOLE_Y, SERVO_HOLE_Y])
+            translate([inner_w/2 + YOKE_WALL_T + SERVO_D/2,
+                       YOKE_BASE_T - M3_NUT_H - 0.5,
+                       arm_z_total - SERVO_H/2 + sz])
+                rotate([90, 0, 0])
+                    cylinder(d = M3_NUT_AF / cos(30), h = M3_NUT_H + 0.5,
+                             $fn = 6);
+
+        // ── Lightening slots in yoke arms ─────────────────────────────────
+        translate([-inner_w/2 - YOKE_WALL_T/2,
+                   YOKE_BASE_T/2,
+                   YOKE_BASE_T + YOKE_ARM_H/2 - 10])
+            cube([YOKE_WALL_T - 2, YOKE_BASE_T - 2, YOKE_ARM_H - 24],
+                 center = true);
+        translate([inner_w/2 + YOKE_WALL_T/2,
+                   YOKE_BASE_T/2,
+                   YOKE_BASE_T + YOKE_ARM_H/2 - 10])
+            cube([YOKE_WALL_T - 2, YOKE_BASE_T - 2, YOKE_ARM_H - 30],
+                 center = true);
+    }
+}
+
+// ============================================================
+// PART 3 — TILT HORN PLATE
+// ============================================================
+// Disc plate bolting to tilt ST3215 servo horn on the right yoke arm.
+// Servo horn spline centres into disc bore (captured, no free rotation).
+// Camera cradle attaches to opposite face via 2× M3 bolts.
+//
+// Tilt range: ±45° limited by yoke arm geometry.
+// Plate thickness HORN_PLATE_T provides stiffness for cantilevered cradle.
+//
+// Print: flat (disc face down), PETG, 5 perims, 50 % infill.
+module tilt_horn_plate() {
+    plate_od = HORN_OD + 8;   // plate OD (4 mm rim outside horn BC)
+
+    difference() {
+        union() {
+            // ── Main disc ─────────────────────────────────────────────────
+            cylinder(d = plate_od, h = HORN_PLATE_T);
+
+            // ── Cradle attachment arm (extends to camera cradle) ──────────
+            // Rectangular boss on top of disc toward camera
+            translate([-CAM_W/2, HORN_PLATE_T - e, -CAM_H/2])
+                cube([CAM_W, HORN_PLATE_T + 4, CAM_H]);
+        }
+
+        // ── Servo horn spline bore (centre) ───────────────────────────────
+        translate([0, 0, -e])
+            cylinder(d = HORN_SPLINE_D, h = HORN_PLATE_T + 2*e);
+
+        // ── Horn bolt holes (4× M3 on HORN_BC_D) ─────────────────────────
+        for (a = [45, 135, 225, 315])
+            translate([HORN_BC_D/2 * cos(a),
+                       HORN_BC_D/2 * sin(a), -e])
+                cylinder(d = HORN_BOLT_D, h = HORN_PLATE_T + 2*e);
+
+        // ── Pivot axle bore (M4, coaxial with horn centre) ────────────────
+        translate([0, 0, -e])
+            cylinder(d = PIVOT_D, h = HORN_PLATE_T + 2*e);
+
+        // ── Cradle attachment bolts (2× M3 in arm boss) ──────────────────
+        for (cz = [-CAM_H/2 + 6, CAM_H/2 - 6])
+            translate([0, HORN_PLATE_T + 2, cz])
+                rotate([90, 0, 0])
+                    cylinder(d = M3_D, h = HORN_PLATE_T + 6 + 2*e);
+
+        // ── M3 hex nut pockets (rear of disc face) ────────────────────────
+        for (cz = [-CAM_H/2 + 6, CAM_H/2 - 6])
+            translate([0, M3_NUT_H + 0.5, cz])
+                rotate([90, 0, 0])
+                    cylinder(d = M3_NUT_AF / cos(30),
+                             h = M3_NUT_H + 0.5, $fn = 6);
+
+        // ── Weight-relief arcs (between horn bolt holes) ──────────────────
+        for (a = [0, 90, 180, 270])
+            translate([(plate_od/2 - 5) * cos(a),
+                       (plate_od/2 - 5) * sin(a), -e])
+                cylinder(d = 6, h = HORN_PLATE_T + 2*e);
+    }
+}
+
+// ============================================================
+// PART 4 — CAMERA CRADLE
+// ============================================================
+// Open-front U-cradle holding D435i via captured 1/4-20 hex nut.
+// Front lip retains camera from sliding forward (+Y).
+// Vibration-damping pads seat in recessed pockets on inner faces.
+// USB-C cable routing channel exits cradle right rear wall.
+//
+// 1/4-20 captured nut in cradle floor — tighten with standard
+// tripod screw or M6→1/4-20 adapter from camera bottom.
+//
+// Print: cradle-floor-down (flat), PETG, 5 perims, 40 % gyroid.
+// No supports needed (overhangs < 45°).
+module camera_cradle() {
+    outer_w = CAM_W + 2*CRADLE_WALL_T;
+    outer_h = CAM_H + CRADLE_FLOOR_T;
+
+    difference() {
+        union() {
+            // ── Cradle body ───────────────────────────────────────────────
+            translate([-outer_w/2, 0, 0])
+                cube([outer_w, CAM_D + CRADLE_WALL_T, outer_h]);
+
+            // ── Front retaining lip ───────────────────────────────────────
+            translate([-outer_w/2, CAM_D + CRADLE_WALL_T - CRADLE_LIP_T, 0])
+                cube([outer_w, CRADLE_LIP_T, CRADLE_LIP_H]);
+
+            // ── Cable channel boss (right rear, exits +X side) ────────────
+            translate([CAM_W/2 + CRADLE_WALL_T - e,
+                       0,
+                       CRADLE_FLOOR_T + CAM_H/2 - CABLE_CH_H/2])
+                cube([CABLE_CH_W + CRADLE_WALL_T, CAM_D * 0.6, CABLE_CH_H]);
+
+            // ── Tilt horn attachment tabs (left + right, bolt to horn plate)─
+            for (sx = [-outer_w/2 - 4, outer_w/2])
+                translate([sx, CAM_D/2, CRADLE_FLOOR_T + CAM_H/2 - 6])
+                    cube([4, 12, 12]);
+        }
+
+        // ── Camera pocket (hollow interior) ──────────────────────────────
+        translate([-CAM_W/2, 0, CRADLE_FLOOR_T])
+            cube([CAM_W, CAM_D + CRADLE_WALL_T + e, CAM_H + e]);
+
+        // ── 1/4-20 UNC clearance bore (camera tripod thread, bottom) ─────
+        translate([CAM_MOUNT_X, CAM_MOUNT_Y, -e])
+            cylinder(d = QTR20_D, h = CRADLE_FLOOR_T + 2*e);
+
+        // ── 1/4-20 hex nut pocket (captured in cradle floor) ─────────────
+        translate([CAM_MOUNT_X, CAM_MOUNT_Y, CRADLE_FLOOR_T - QTR20_NUT_H - 0.5])
+            cylinder(d = QTR20_NUT_AF / cos(30),
+                     h = QTR20_NUT_H + 0.6, $fn = 6);
+
+        // ── USB-C cable channel (exit through right rear wall) ────────────
+        translate([CAM_W/2 - e,
+                   0,
+                   CRADLE_FLOOR_T + CAM_H/2 - CABLE_CH_H/2])
+            cube([CABLE_CH_W + CRADLE_WALL_T + 2*e,
+                  CAM_D * 0.6 + e, CABLE_CH_H]);
+
+        // ── Vibe pad recesses on inner camera-contact faces ───────────────
+        // Rear wall recess (camera front face → +Y side of rear wall)
+        translate([-CAM_W/2 + CRADLE_WALL_T, CRADLE_WALL_T, CRADLE_FLOOR_T])
+            cube([CAM_W, PAD_T, CAM_H]);
+
+        // ── Tilt horn bolt holes in attachment tabs ───────────────────────
+        for (sx = [-outer_w/2 - 4 - e, outer_w/2 - e])
+            translate([sx, CAM_D/2 + 6, CRADLE_FLOOR_T + CAM_H/2])
+                rotate([0, 90, 0])
+                    cylinder(d = M3_D, h = 6 + 2*e);
+
+        // ── M3 nut pockets in attachment tabs ─────────────────────────────
+        translate([outer_w/2 + 4 - M3_NUT_H - 0.4,
+                   CAM_D/2 + 6,
+                   CRADLE_FLOOR_T + CAM_H/2])
+            rotate([0, 90, 0])
+                cylinder(d = M3_NUT_AF / cos(30),
+                         h = M3_NUT_H + 0.4, $fn = 6);
+        translate([-outer_w/2 - 4 - e,
+                   CAM_D/2 + 6,
+                   CRADLE_FLOOR_T + CAM_H/2])
+            rotate([0, 90, 0])
+                cylinder(d = M3_NUT_AF / cos(30),
+                         h = M3_NUT_H + 0.4, $fn = 6);
+
+        // ── Lightening pockets in cradle walls ────────────────────────────
+        for (face_x = [-CAM_W/2 - CRADLE_WALL_T - e, CAM_W/2 - e])
+            translate([face_x, CAM_D * 0.2, CRADLE_FLOOR_T + 3])
+                cube([CRADLE_WALL_T + 2*e, CAM_D * 0.55, CAM_H - 6]);
+    }
+}
+
+// ============================================================
+// PART 5 — VIBRATION-DAMPING PAD
+// ============================================================
+// Flat pad with transverse PETG flexure ribs pressing against camera body.
+// Rib geometry (thin fins ~1.5 mm tall) deflects under camera vibration,
+// attenuating high-frequency input from motor/drive-train.
+// For superior damping: print in TPU 95A (no infill changes needed).
+// Pads seat in recessed pockets in camera cradle inner wall.
+// Optional M2 bolt-through at corners or adhesive-back foam tape.
+//
+// Print: pad-back-face-down, PETG or TPU 95A, 3 perims, 20 % infill.
+module vibe_pad() {
+    rib_count = floor((PAD_W - RIB_W) / RIB_PITCH);
+
+    union() {
+        // ── Base plate ────────────────────────────────────────────────────
+        translate([-PAD_W/2, -PAD_T, -PAD_H/2])
+            cube([PAD_W, PAD_T, PAD_H]);
+
+        // ── Flexure ribs (parallel to Z, spaced RIB_PITCH apart) ─────────
+        for (i = [0 : rib_count - 1]) {
+            rx = -PAD_W/2 + RIB_PITCH/2 + i * RIB_PITCH + RIB_W/2;
+            if (rx <= PAD_W/2 - RIB_W/2)
+                translate([rx, 0, 0])
+                    cube([RIB_W, RIB_H, PAD_H - 6], center = true);
+        }
+
+        // ── Corner nubs (M2 bolt-through retention, optional) ─────────────
+        for (px = [-PAD_W/2 + 5, PAD_W/2 - 5])
+        for (pz = [-PAD_H/2 + 5, PAD_H/2 - 5])
+            translate([px, -PAD_T/2, pz])
+                difference() {
+                    cylinder(d = 5, h = PAD_T, center = true);
+                    cylinder(d = 2.4, h = PAD_T + 2*e, center = true);
+                }
+    }
+}

chassis/ip54_BOM.md

@@ -104,7 +104,11 @@ IP54-rated enclosures and sensor housings for all-weather outdoor robot operatio
 | Component | Thermal strategy | Max junction | Enclosure budget |
 |-----------|-----------------|-------------|-----------------|
 | Jetson Orin NX | Al pad → lid → fan forced convection | 95 °C Tj | Target ≤ 60 °C case |
-| FC (MAMBA F722S) | Passive; FC has own EMI shield | 85 °C | <60 °C ambient OK |
+<<<<<<< HEAD
+| FC (ESP32 BALANCE) | Passive; FC has own EMI shield | 85 °C | <60 °C ambient OK |
+=======
+| FC (ESP32-S3 BALANCE) | Passive; FC has own EMI shield | 85 °C | <60 °C ambient OK |
+>>>>>>> 291dd68 (feat: remove all STM32/Mamba/BlackPill references — ESP32-S3 only)
 | ESC × 2 | Al pad → lid | 100 °C Tj | Target ≤ 60 °C |
 | D435i | Passive; housing vent gap on rear cap | 45 °C surface | — |
 

chassis/jetson_orin_mount.scad

@@ -0,0 +1,386 @@
+// ============================================================
+// Jetson Orin Nano Carrier Board Mount — Issue #612
+// Agent   : sl-mechanical
+// Date    : 2026-03-15
+// Part catalogue:
+//   1. tnut_base     — 2020 T-slot rail interface plate, M5 T-nut captive pockets
+//   2. standoff_post — M2.5 captive-nut standoff post (×4), 10 mm airflow gap
+//   3. side_brace    — lateral stiffening brace with port-access cutouts (×2)
+//   4. duct_shroud   — optional top heatsink duct / fan-exhaust channel
+//   5. cable_clip    — snap-on cable management clip for brace edge
+//
+// BOM:
+//   4 × M5×10 BHCS + M5 T-nuts          (tnut_base to rail, 2 per rail)
+//   4 × M2.5×20 SHCS                    (board to standoff posts)
+//   4 × M2.5 hex nuts                   (captured in standoff posts)
+//   4 × M3×8  SHCS + washers            (side_brace to tnut_base)
+//   2 × M3×16 SHCS                      (duct_shroud to side_brace tops)
+//
+// Jetson Orin Nano carrier board (Seeed reComputer / official dev kit):
+//   Board dims   : 100 × 80 mm
+//   Mounting hole pattern : 86 × 58 mm (centre-to-centre), M2.5, Ø3.5 pad
+//   PCB thickness: 1.6 mm
+//   Connector side: -Y (USB-A, USB-C, HDMI, DP, GbE, SD on one long edge)
+//   Fan header & PWM header: +X short edge
+//   M.2 / NVMe: bottom face
+//
+// Print settings (PETG):
+//   tnut_base / standoff_post / side_brace / duct_shroud : 5 perimeters, 40 % gyroid, no supports
+//   cable_clip                                            : 3 perimeters, 30 % gyroid, no supports
+//
+// Export commands:
+//   openscad -D 'RENDER="tnut_base"'     -o tnut_base.stl     jetson_orin_mount.scad
+//   openscad -D 'RENDER="standoff_post"' -o standoff_post.stl jetson_orin_mount.scad
+//   openscad -D 'RENDER="side_brace"'    -o side_brace.stl    jetson_orin_mount.scad
+//   openscad -D 'RENDER="duct_shroud"'   -o duct_shroud.stl   jetson_orin_mount.scad
+//   openscad -D 'RENDER="cable_clip"'    -o cable_clip.stl    jetson_orin_mount.scad
+//   openscad -D 'RENDER="assembly"'      -o assembly.png      jetson_orin_mount.scad
+// ============================================================
+
+// ── Render selector ─────────────────────────────────────────
+RENDER = "assembly"; // tnut_base | standoff_post | side_brace | duct_shroud | cable_clip | assembly
+
+// ── Global constants ────────────────────────────────────────
+$fn = 64;
+EPS = 0.01;
+
+// 2020 rail
+RAIL_W      = 20.0;
+SLOT_NECK_H =  3.2;
+TNUT_W      =  9.8;
+TNUT_H      =  5.5;
+TNUT_L      = 12.0;
+M5_D        =  5.2;
+M5_HEAD_D   =  9.5;
+M5_HEAD_H   =  4.0;
+
+// Jetson Orin Nano carrier board
+BOARD_L     = 100.0;  // board X
+BOARD_W     =  80.0;  // board Y
+BOARD_T     =   1.6;  // PCB thickness
+MH_SX       =  86.0;  // mounting hole span X (centre-to-centre)
+MH_SY       =  58.0;  // mounting hole span Y
+M25_D       =   2.7;  // M2.5 clearance bore
+M25_NUT_W   =   5.0;  // M2.5 hex nut across-flats
+M25_NUT_H   =   2.0;  // M2.5 hex nut height
+M25_HEAD_D  =   5.0;  // M2.5 SHCS head diameter
+M25_HEAD_H  =   2.5;
+
+// Base plate
+BASE_L      = 120.0;  // length along X (covers board + overhang for braces)
+BASE_W      =  50.0;  // width along Y (rail mount footprint)
+BASE_T      =   6.0;  // plate thickness
+BOLT_PITCH  =  40.0;  // M5 rail bolt pitch (per rail, 2 rails at Y=0 & Y=BASE_W)
+M3_D        =   3.2;
+M3_HEAD_D   =   6.0;
+M3_HEAD_H   =   3.0;
+
+// Standoff posts
+POST_H      =  12.0;  // airflow gap + PCB seating (>= 10 mm clearance spec)
+POST_OD     =   8.0;  // outer diameter
+POST_BASE_D =  11.0;  // flange diameter
+POST_BASE_H =   3.0;  // flange height
+NUT_TRAP_H  = M25_NUT_H + 0.3;
+NUT_TRAP_W  = M25_NUT_W + 0.4;
+
+// Side braces
+BRACE_T     =   5.0;  // brace thickness (X)
+BRACE_H     = POST_H + POST_BASE_H + BOARD_T + 4.0;  // full height
+BRACE_W     = BASE_W;  // same width as base
+
+// Port-access cutouts (connector side -Y)
+USB_CUT_W   =  60.0;  // wide cutout for USB-A stack + HDMI + DP
+USB_CUT_H   =  22.0;
+GBE_CUT_W   =  20.0;  // GbE jack
+GBE_CUT_H   =  18.0;
+
+// Duct shroud
+DUCT_T      =   3.0;  // wall thickness
+DUCT_FLANGE =   6.0;  // side tab width for M3 attachment
+FAN_W       =  40.0;  // standard 40 mm blower clearance cutout
+FAN_H       =  10.0;  // duct outlet height
+
+// Cable clip
+CLIP_OD     =  12.0;
+CLIP_ID     =   7.0;
+CLIP_GAP    =   7.5;
+CLIP_W      =  10.0;
+SNAP_T      =   1.8;
+
+// ── Utilities ───────────────────────────────────────────────
+module chamfer_cube(size, ch=1.0) {
+    hull() {
+        translate([ch, ch, 0])          cube([size[0]-2*ch, size[1]-2*ch, EPS]);
+        translate([0, 0, ch])           cube(size - [0, 0, ch]);
+    }
+}
+
+module hex_pocket(af, depth) {
+    cylinder(d=af/cos(30), h=depth, $fn=6);
+}
+
+// ── Part 1: tnut_base ───────────────────────────────────────
+module tnut_base() {
+    difference() {
+        union() {
+            chamfer_cube([BASE_L, BASE_W, BASE_T], ch=1.5);
+
+            // Raised mounting bosses for M3 brace attachment (4 corners)
+            for (x = [8, BASE_L-8])
+                for (y = [8, BASE_W-8])
+                    translate([x, y, BASE_T])
+                        cylinder(d=10, h=2.5);
+        }
+
+        // T-nut pockets and M5 bolts — front rail (y = BASE_W/4)
+        for (x = [BASE_L/2 - BOLT_PITCH/2, BASE_L/2 + BOLT_PITCH/2]) {
+            translate([x, BASE_W/4, -EPS]) {
+                cylinder(d=M5_D, h=BASE_T + 2*EPS);
+                cylinder(d=M5_HEAD_D, h=M5_HEAD_H + EPS);
+            }
+            translate([x - TNUT_L/2, BASE_W/4 - TNUT_W/2, BASE_T - TNUT_H])
+                cube([TNUT_L, TNUT_W, TNUT_H + EPS]);
+        }
+
+        // T-nut pockets and M5 bolts — rear rail (y = 3*BASE_W/4)
+        for (x = [BASE_L/2 - BOLT_PITCH/2, BASE_L/2 + BOLT_PITCH/2]) {
+            translate([x, 3*BASE_W/4, -EPS]) {
+                cylinder(d=M5_D, h=BASE_T + 2*EPS);
+                cylinder(d=M5_HEAD_D, h=M5_HEAD_H + EPS);
+            }
+            translate([x - TNUT_L/2, 3*BASE_W/4 - TNUT_W/2, BASE_T - TNUT_H])
+                cube([TNUT_L, TNUT_W, TNUT_H + EPS]);
+        }
+
+        // M3 boss bolt holes (corner braces)
+        for (x = [8, BASE_L-8])
+            for (y = [8, BASE_W-8])
+                translate([x, y, -EPS])
+                    cylinder(d=M3_D, h=BASE_T + 2.5 + 2*EPS);
+
+        // M3 boss counterbores (head from bottom)
+        for (x = [8, BASE_L-8])
+            for (y = [8, BASE_W-8])
+                translate([x, y, -EPS])
+                    cylinder(d=M3_HEAD_D, h=M3_HEAD_H + EPS);
+
+        // Standoff post seating holes (board hole pattern, centred on plate)
+        bx0 = BASE_L/2 - MH_SX/2;
+        by0 = BASE_W/2 - MH_SY/2;
+        for (dx = [0, MH_SX])
+            for (dy = [0, MH_SY])
+                translate([bx0+dx, by0+dy, -EPS])
+                    cylinder(d=POST_BASE_D + 0.4, h=BASE_T + 2*EPS);
+
+        // Weight relief grid (2 pockets)
+        translate([20, 12, -EPS]) cube([30, BASE_W-24, BASE_T/2]);
+        translate([BASE_L-50, 12, -EPS]) cube([30, BASE_W-24, BASE_T/2]);
+
+        // Cable pass-through slot
+        translate([BASE_L/2 - 8, BASE_W/2 - 3, -EPS])
+            cube([16, 6, BASE_T + 2*EPS]);
+    }
+}
+
+// ── Part 2: standoff_post ───────────────────────────────────
+module standoff_post() {
+    difference() {
+        union() {
+            // Flange
+            cylinder(d=POST_BASE_D, h=POST_BASE_H);
+            // Post body
+            translate([0, 0, POST_BASE_H])
+                cylinder(d=POST_OD, h=POST_H);
+        }
+
+        // M2.5 through bore
+        translate([0, 0, -EPS])
+            cylinder(d=M25_D, h=POST_BASE_H + POST_H + 2*EPS);
+
+        // Captured hex nut trap (from top)
+        translate([0, 0, POST_BASE_H + POST_H - NUT_TRAP_H])
+            hex_pocket(NUT_TRAP_W, NUT_TRAP_H + EPS);
+
+        // Anti-rotation flat on nut pocket
+        translate([-M25_NUT_W/2 - 0.2, -POST_OD/2 - EPS,
+                   POST_BASE_H + POST_H - NUT_TRAP_H])
+            cube([M25_NUT_W + 0.4, 2.0, NUT_TRAP_H + EPS]);
+    }
+}
+
+// ── Part 3: side_brace ──────────────────────────────────────
+// Printed as +X face. Mirror for -X side.
+module side_brace() {
+    difference() {
+        union() {
+            chamfer_cube([BRACE_T, BRACE_W, BRACE_H], ch=1.0);
+
+            // Top lip to retain board edge
+            translate([0, 0, BRACE_H])
+                cube([BRACE_T + 8.0, BRACE_W, 2.5]);
+        }
+
+        // M3 bolt holes at base (attach to tnut_base bosses)
+        for (y = [8, BRACE_W-8])
+            translate([-EPS, y, 4])
+                rotate([0, 90, 0])
+                    cylinder(d=M3_D, h=BRACE_T + 2*EPS);
+
+        // M3 counterbore from outer face
+        for (y = [8, BRACE_W-8])
+            translate([-EPS, y, 4])
+                rotate([0, 90, 0])
+                    cylinder(d=M3_HEAD_D, h=M3_HEAD_H + EPS);
+
+        // Port-access cutout — USB/HDMI/DP cluster (centred on brace face)
+        translate([-EPS, BRACE_W/2 - USB_CUT_W/2, POST_BASE_H + 2.0])
+            cube([BRACE_T + 2*EPS, USB_CUT_W, USB_CUT_H]);
+
+        // GbE cutout (offset toward +Y)
+        translate([-EPS, BRACE_W/2 + USB_CUT_W/2 - GBE_CUT_W - 2, POST_BASE_H + 2.0])
+            cube([BRACE_T + 2*EPS, GBE_CUT_W, GBE_CUT_H]);
+
+        // M3 duct attachment holes (top edge)
+        for (y = [BRACE_W/4, 3*BRACE_W/4])
+            translate([BRACE_T/2, y, BRACE_H - 2])
+                cylinder(d=M3_D, h=10);
+
+        // Ventilation slots (3 tall slots for airflow)
+        for (i = [0:2])
+            translate([-EPS,
+                       (BRACE_W - 3*8 - 2*4) / 2 + i*(8+4),
+                       POST_BASE_H + USB_CUT_H + 6])
+                cube([BRACE_T + 2*EPS, 8, BRACE_H - POST_BASE_H - USB_CUT_H - 10]);
+    }
+}
+
+// ── Part 4: duct_shroud ─────────────────────────────────────
+// Top cap that channels fan exhaust away from board; optional print.
+module duct_shroud() {
+    duct_l = BASE_L - 2*BRACE_T - 1.0;  // span between inner brace faces
+    duct_w = BRACE_W;
+
+    difference() {
+        union() {
+            // Top plate
+            cube([duct_l, duct_w, DUCT_T]);
+
+            // Front wall (fan inlet side)
+            translate([0, 0, -FAN_H])
+                cube([DUCT_T, duct_w, FAN_H + DUCT_T]);
+
+            // Rear wall (exhaust side — open centre)
+            translate([duct_l - DUCT_T, 0, -FAN_H])
+                cube([DUCT_T, duct_w, FAN_H + DUCT_T]);
+
+            // Side flanges for M3 attachment
+            translate([-DUCT_FLANGE, 0, -FAN_H])
+                cube([DUCT_FLANGE, duct_w, FAN_H + DUCT_T]);
+            translate([duct_l, 0, -FAN_H])
+                cube([DUCT_FLANGE, duct_w, FAN_H + DUCT_T]);
+        }
+
+        // Fan cutout on top plate (centred)
+        translate([duct_l/2 - FAN_W/2, duct_w/2 - FAN_W/2, -EPS])
+            cube([FAN_W, FAN_W, DUCT_T + 2*EPS]);
+
+        // Fan screw holes (40 mm fan, Ø3.2 at 32 mm BC)
+        for (dx = [-16, 16])
+            for (dy = [-16, 16])
+                translate([duct_l/2 + dx, duct_w/2 + dy, -EPS])
+                    cylinder(d=M3_D, h=DUCT_T + 2*EPS);
+
+        // Exhaust slot on rear wall (full width minus corners)
+        translate([duct_l - DUCT_T - EPS, 4, -FAN_H + 2])
+            cube([DUCT_T + 2*EPS, duct_w - 8, FAN_H - 2]);
+
+        // M3 flange attachment holes
+        for (y = [duct_w/4, 3*duct_w/4]) {
+            translate([-DUCT_FLANGE - EPS, y, -FAN_H/2])
+                rotate([0, 90, 0])
+                    cylinder(d=M3_D, h=DUCT_FLANGE + 2*EPS);
+            translate([duct_l + DUCT_T - EPS, y, -FAN_H/2])
+                rotate([0, 90, 0])
+                    cylinder(d=M3_D, h=DUCT_FLANGE + 2*EPS);
+        }
+    }
+}
+
+// ── Part 5: cable_clip ──────────────────────────────────────
+module cable_clip() {
+    difference() {
+        union() {
+            // Snap-wrap body
+            difference() {
+                cylinder(d=CLIP_OD + 2*SNAP_T, h=CLIP_W);
+                translate([0, 0, -EPS])
+                    cylinder(d=CLIP_ID, h=CLIP_W + 2*EPS);
+                // Front gap
+                translate([-CLIP_GAP/2, 0, -EPS])
+                    cube([CLIP_GAP, CLIP_OD, CLIP_W + 2*EPS]);
+            }
+
+            // Mounting tab for brace edge
+            translate([CLIP_OD/2 + SNAP_T - EPS, -SNAP_T, 0])
+                cube([8, SNAP_T*2, CLIP_W]);
+        }
+
+        // Tab screw hole
+        translate([CLIP_OD/2 + SNAP_T + 4, 0, CLIP_W/2])
+            rotate([90, 0, 0])
+                cylinder(d=M3_D, h=SNAP_T*2 + 2*EPS, center=true);
+    }
+}
+
+// ── Assembly ────────────────────────────────────────────────
+module assembly() {
+    // Base plate
+    color("SteelBlue")
+        tnut_base();
+
+    // Standoff posts (board hole pattern)
+    bx0 = BASE_L/2 - MH_SX/2;
+    by0 = BASE_W/2 - MH_SY/2;
+    for (dx = [0, MH_SX])
+        for (dy = [0, MH_SY])
+            color("DodgerBlue")
+                translate([bx0+dx, by0+dy, BASE_T])
+                    standoff_post();
+
+    // Side braces (left and right)
+    color("CornflowerBlue")
+        translate([0, 0, BASE_T])
+            side_brace();
+    color("CornflowerBlue")
+        translate([BASE_L, BRACE_W, BASE_T])
+            mirror([1, 0, 0])
+                mirror([0, 1, 0])
+                    side_brace();
+
+    // Board silhouette (translucent, for clearance visualisation)
+    color("ForestGreen", 0.25)
+        translate([BASE_L/2 - BOARD_L/2, BASE_W/2 - BOARD_W/2,
+                   BASE_T + POST_BASE_H + POST_H])
+            cube([BOARD_L, BOARD_W, BOARD_T]);
+
+    // Duct shroud (above board)
+    color("LightSteelBlue", 0.7)
+        translate([BRACE_T + 0.5, 0,
+                   BASE_T + POST_BASE_H + POST_H + BOARD_T + 2.0])
+            duct_shroud();
+
+    // Cable clips (on brace edge, 2×)
+    for (y = [BRACE_W/3, 2*BRACE_W/3])
+        color("SlateGray")
+            translate([BASE_L + 2, y, BASE_T + BRACE_H/2 - CLIP_W/2])
+                rotate([0, 90, 0])
+                    cable_clip();
+}
+
+// ── Dispatch ────────────────────────────────────────────────
+if      (RENDER == "tnut_base")     tnut_base();
+else if (RENDER == "standoff_post") standoff_post();
+else if (RENDER == "side_brace")    side_brace();
+else if (RENDER == "duct_shroud")   duct_shroud();
+else if (RENDER == "cable_clip")    cable_clip();
+else                                assembly();

chassis/phone_mount_bracket.scad

@@ -0,0 +1,504 @@
+// ============================================================
+// phone_mount_bracket.scad — Spring-Loaded Phone Mount for T-Slot Rail
+// Issue: #535  Agent: sl-mechanical  Date: 2026-03-07
+// ============================================================
+//
+// Parametric spring-loaded phone mount that clamps to the 2020 aluminium
+// T-slot sensor rail.  Adjustable phone width 60–85 mm.  Quick-release
+// cam lever for tool-free phone swap.  Vibration-damping flexure ribs
+// on grip pads absorb motor/terrain vibration (PETG compliance).
+//
+// Design overview:
+//   - Fixed jaw + sliding jaw on a 40 mm guide rail (M4 rod)
+//   - Coil spring (Ø8 × 30 mm) compressed between jaw and end-stop —
+//     spring pre-load keeps phone clamped at any width in range
+//   - Cam lever (printed PETG) rotates 90° to release / lock spring
+//   - Anti-vibration flexure ribs on both grip pad faces
+//   - Landscape or portrait orientation: bracket rotates on T-nut base
+//
+// Parts (STL exports):
+//   Part 1 — tnut_base()          Rail attachment base (universal)
+//   Part 2 — fixed_jaw()          Fixed bottom jaw + guide rail bosses
+//   Part 3 — sliding_jaw()        Spring-loaded sliding jaw
+//   Part 4 — cam_lever()          Quick-release cam lever
+//   Part 5 — grip_pad()           Flexure grip pad (print ×2, TPU optional)
+//   Part 6 — assembly_preview()   Full assembly
+//
+// Hardware BOM (per mount):
+//   1× M4 × 60 mm SHCS          guide rod + spring bolt
+//   1× M4 hex nut                end-stop on sliding jaw
+//   1× Ø8 × 30 mm coil spring   ~0.5 N/mm rate (spring clamping)
+//   2× M3 × 16 mm SHCS          T-nut base thumbscrew + arm bolts
+//   1× M3 hex nut                thumbscrew nut in T-nut
+//   4× M2 × 8 mm SHCS           grip pad retention bolts (optional)
+//
+// Dimensions:
+//   Phone width range : PHONE_W_MIN–PHONE_W_MAX (60–85 mm) parametric
+//   Phone thickness   : up to PHONE_THICK_MAX (12 mm) — open-front jaw
+//   Phone height held : GRIP_SPAN (22 mm each jaw) — portrait/landscape
+//   Overall bracket H : ~110 mm  W: ~90 mm  D: ~55 mm
+//
+// Print settings:
+//   Material  : PETG (tnut_base, fixed_jaw, sliding_jaw, cam_lever)
+//               TPU 95A optional for grip_pad (or PETG for rigidity)
+//   Perimeters: 5 (structural parts), 3 (grip_pad)
+//   Infill    : 40 % gyroid (jaws), 20 % (grip_pad)
+//   Supports  : none needed (designed for FDM orientation)
+//   Layer ht  : 0.2 mm
+//
+// Export commands:
+//   openscad phone_mount_bracket.scad -D 'RENDER="tnut_base_stl"'    -o pm_tnut_base.stl
+//   openscad phone_mount_bracket.scad -D 'RENDER="fixed_jaw_stl"'    -o pm_fixed_jaw.stl
+//   openscad phone_mount_bracket.scad -D 'RENDER="sliding_jaw_stl"'  -o pm_sliding_jaw.stl
+//   openscad phone_mount_bracket.scad -D 'RENDER="cam_lever_stl"'    -o pm_cam_lever.stl
+//   openscad phone_mount_bracket.scad -D 'RENDER="grip_pad_stl"'     -o pm_grip_pad.stl
+// ============================================================
+
+$fn = 64;
+e   = 0.01;   // epsilon for boolean clearance
+
+// ── Phone parameters (adjust to target device) ───────────────────────────────
+PHONE_W_MIN    = 60.0;   // narrowest phone width supported (mm)
+PHONE_W_MAX    = 85.0;   // widest phone width supported (mm)
+PHONE_THICK_MAX = 12.0;  // max phone body thickness incl. case (mm)
+
+// ── Rail geometry (must match sensor_rail.scad) ──────────────────────────────
+RAIL_W         = 20.0;
+SLOT_OPEN      =  6.0;
+SLOT_INNER_W   = 10.2;
+SLOT_INNER_H   =  5.8;
+SLOT_NECK_H    =  3.2;
+
+// ── T-nut constants ───────────────────────────────────────────────────────────
+TNUT_W         =  9.8;
+TNUT_H         =  5.5;
+TNUT_L         = 12.0;
+TNUT_M3_NUT_AF =  5.5;
+TNUT_M3_NUT_H  =  2.5;
+TNUT_BOLT_D    =  3.3;   // M3 clearance
+
+// ── Base plate geometry ───────────────────────────────────────────────────────
+BASE_FACE_W  = 30.0;
+BASE_FACE_H  = 25.0;
+BASE_FACE_T  = SLOT_NECK_H + 1.5;
+
+// ── Jaw geometry ─────────────────────────────────────────────────────────────
+JAW_BODY_W   = 88.0;    // jaw outer width (> PHONE_W_MAX for rim)
+JAW_BODY_H   = 28.0;    // jaw height (Z) — phone grip span
+JAW_BODY_T   = 14.0;    // jaw depth (Y) — phone cradled this deep
+JAW_WALL_T   =  4.0;    // jaw side wall thickness
+JAW_LIP_T    =  3.0;    // front retaining lip thickness
+JAW_LIP_H    =  5.0;    // front lip height (retains phone)
+PHONE_POCKET_D = PHONE_THICK_MAX + 0.5;  // pocket depth for phone
+
+// ── Guide rod / spring system ─────────────────────────────────────────────────
+GUIDE_ROD_D  =  4.3;    // M4 clearance bore in sliding jaw
+GUIDE_BOSS_D = 10.0;    // boss OD around guide bore
+GUIDE_BOSS_T =  6.0;    // boss length
+SPRING_OD    =  8.5;    // coil spring OD pocket (spring is Ø8)
+SPRING_L     = 32.0;    // spring pocket length (spring compressed ~22 mm)
+SPRING_SEAT_T =  3.0;   // spring seat wall at end-stop boss
+JAW_TRAVEL   = PHONE_W_MAX - PHONE_W_MIN + 4.0;   // max jaw travel (mm)
+ARM_SPAN     = PHONE_W_MAX + 2 * JAW_WALL_T + 8;  // fixed jaw total width
+
+// ── Cam lever geometry ────────────────────────────────────────────────────────
+CAM_R_MIN    =  5.0;    // cam small radius (engaged / clamped)
+CAM_R_MAX    =  9.0;    // cam large radius (released, spring compressed)
+CAM_THICK    =  8.0;    // cam disc thickness
+CAM_HANDLE_L = 45.0;    // lever arm length
+CAM_HANDLE_W =  8.0;    // lever handle width
+CAM_HANDLE_T =  5.0;    // lever handle thickness
+CAM_BORE_D   =  4.3;    // M4 pivot bore
+CAM_DETENT_D =  3.0;    // detent ball pocket (3 mm bearing)
+
+// ── Grip pad geometry (vibration dampening flexure ribs) ─────────────────────
+PAD_W        = JAW_BODY_W - 2*JAW_WALL_T - 2;  // pad width
+PAD_H        = JAW_BODY_H - 2;                  // pad height
+PAD_T        =  2.5;    // pad body thickness
+RIB_H        =  1.5;    // flexure rib height above pad face
+RIB_W        =  1.2;    // rib width
+RIB_PITCH    =  5.0;    // rib pitch (centre-to-centre)
+RIB_COUNT    = floor(PAD_W / RIB_PITCH) - 1;
+
+// ── Arm geometry (base to jaw body) ──────────────────────────────────────────
+ARM_REACH    = 38.0;    // distance from rail face to jaw centreline (+Y)
+ARM_T        =  4.0;    // arm thickness
+ARM_H        = BASE_FACE_H;
+
+// ── Fasteners ─────────────────────────────────────────────────────────────────
+M2_D = 2.4;
+M3_D = 3.3;
+M4_D = 4.3;
+M4_NUT_AF = 7.0;   // M4 hex nut across-flats
+M4_NUT_H  = 3.2;   // M4 hex nut height
+
+// ============================================================
+// RENDER DISPATCH
+// ============================================================
+RENDER = "assembly";
+
+if      (RENDER == "assembly")        assembly_preview();
+else if (RENDER == "tnut_base_stl")   tnut_base();
+else if (RENDER == "fixed_jaw_stl")   fixed_jaw();
+else if (RENDER == "sliding_jaw_stl") sliding_jaw();
+else if (RENDER == "cam_lever_stl")   cam_lever();
+else if (RENDER == "grip_pad_stl")    grip_pad();
+
+// ============================================================
+// ASSEMBLY PREVIEW
+// ============================================================
+module assembly_preview() {
+    // Ghost rail section (20 × 20 × 200)
+    %color("Silver", 0.30)
+        linear_extrude(200)
+            square([RAIL_W, RAIL_W], center = true);
+
+    // T-nut base at Z=80 on rail
+    color("OliveDrab", 0.85)
+        translate([0, 0, 80])
+            tnut_base();
+
+    // Fixed jaw assembly (centred, extending +Y from base)
+    color("DarkSlateGray", 0.85)
+        translate([0, SLOT_NECK_H + BASE_FACE_T + ARM_REACH, 80])
+            fixed_jaw();
+
+    // Sliding jaw — shown at mid-travel (phone ~72 mm wide)
+    color("SteelBlue", 0.85)
+        translate([PHONE_W_MIN + (PHONE_W_MAX - PHONE_W_MIN)/2,
+                   SLOT_NECK_H + BASE_FACE_T + ARM_REACH, 80])
+            sliding_jaw();
+
+    // Grip pads on both jaws
+    color("DimGray", 0.85) {
+        translate([0, SLOT_NECK_H + BASE_FACE_T + ARM_REACH, 80])
+            translate([JAW_WALL_T, JAW_BODY_T, JAW_BODY_H/2])
+                rotate([90, 0, 0])
+                    grip_pad();
+        translate([PHONE_W_MIN + (PHONE_W_MAX - PHONE_W_MIN)/2,
+                   SLOT_NECK_H + BASE_FACE_T + ARM_REACH, 80])
+            translate([-JAW_WALL_T - PAD_T, JAW_BODY_T, JAW_BODY_H/2])
+                rotate([90, 0, 180])
+                    grip_pad();
+    }
+
+    // Cam lever — shown in locked (clamped) position
+    color("OrangeRed", 0.85)
+        translate([ARM_SPAN/2 + 6,
+                   SLOT_NECK_H + BASE_FACE_T + ARM_REACH + GUIDE_BOSS_D/2,
+                   80 + JAW_BODY_H/2])
+            rotate([0, 0, 0])
+                cam_lever();
+}
+
+// ============================================================
+// PART 1 — T-NUT BASE
+// ============================================================
+// Standard 2020 T-slot rail attachment base.
+// Identical interface to sensor_rail_brackets.scad universal_tnut_base().
+// Arm extends in +Y; rail clamp bolt in -Y face.
+//
+// Print flat (face plate down), PETG, 5 perims, 60 % infill.
+module tnut_base() {
+    difference() {
+        union() {
+            // Face plate (flush against rail outer face)
+            translate([-BASE_FACE_W/2, -BASE_FACE_T, 0])
+                cube([BASE_FACE_W, BASE_FACE_T, BASE_FACE_H]);
+
+            // T-nut neck (enters rail slot)
+            translate([-TNUT_W/2, 0, (BASE_FACE_H - TNUT_L)/2])
+                cube([TNUT_W, SLOT_NECK_H + e, TNUT_L]);
+
+            // T-nut body (wider, inside T-groove)
+            translate([-TNUT_W/2, SLOT_NECK_H - e, (BASE_FACE_H - TNUT_L)/2])
+                cube([TNUT_W, TNUT_H - SLOT_NECK_H + e, TNUT_L]);
+
+            // Arm stub (face plate → jaw)
+            translate([-BASE_FACE_W/2, -BASE_FACE_T, 0])
+                cube([BASE_FACE_W, BASE_FACE_T + ARM_REACH, ARM_T]);
+        }
+
+        // M3 rail clamp bolt bore (centre of T-nut, through face plate)
+        translate([0, -BASE_FACE_T - e, BASE_FACE_H/2])
+            rotate([-90, 0, 0])
+                cylinder(d = TNUT_BOLT_D, h = BASE_FACE_T + TNUT_H + 2*e);
+
+        // M3 hex nut pocket (inside T-nut body)
+        translate([0, SLOT_NECK_H + 0.3, BASE_FACE_H/2])
+            rotate([-90, 0, 0])
+                cylinder(d = TNUT_M3_NUT_AF / cos(30),
+                         h = TNUT_M3_NUT_H + 0.3,
+                         $fn = 6);
+
+        // 2× M3 bolt holes for arm-to-jaw bolting
+        for (bx = [-10, 10])
+            translate([bx, ARM_REACH - BASE_FACE_T - e, ARM_T/2])
+                rotate([-90, 0, 0])
+                    cylinder(d = M3_D, h = 8 + 2*e);
+
+        // Lightening slot in arm
+        translate([0, -BASE_FACE_T/2 + ARM_REACH/2, ARM_T/2])
+            cube([BASE_FACE_W - 12, ARM_REACH - 16, ARM_T + 2*e],
+                 center = true);
+    }
+}
+
+// ============================================================
+// PART 2 — FIXED JAW
+// ============================================================
+// Fixed lower jaw of the clamping system.  Phone sits in the pocket
+// formed by the fixed jaw (bottom) and sliding jaw (top).
+// Two guide bosses on the right wall carry the M4 guide rod + spring.
+// The cam lever pivot boss is on the outer right face.
+//
+// Coordinate origin: centre-bottom of jaw body.
+// Phone entry face: +Y (open front), phone pocket opens toward +Y.
+// Fixed jaw left edge is at X = -JAW_BODY_W/2.
+//
+// Print jaw-pocket-face down, PETG, 5 perims, 40 % infill.
+module fixed_jaw() {
+    difference() {
+        union() {
+            // ── Main jaw body ────────────────────────────────────────────
+            translate([-JAW_BODY_W/2, -JAW_BODY_T/2, 0])
+                cube([JAW_BODY_W, JAW_BODY_T, JAW_BODY_H]);
+
+            // ── Front retaining lip (keeps phone from falling forward) ───
+            translate([-JAW_BODY_W/2, JAW_BODY_T/2 - JAW_LIP_T, 0])
+                cube([JAW_BODY_W, JAW_LIP_T, JAW_LIP_H]);
+
+            // ── Guide boss right (outer, carries spring + end-stop) ──────
+            translate([JAW_BODY_W/2, 0, JAW_BODY_H/2])
+                rotate([0, 90, 0])
+                    cylinder(d = GUIDE_BOSS_D, h = GUIDE_BOSS_T);
+
+            // ── Cam lever pivot boss (right face, above guide boss) ──────
+            translate([JAW_BODY_W/2, 0, JAW_BODY_H/2 + GUIDE_BOSS_D + 4])
+                rotate([0, 90, 0])
+                    cylinder(d = CAM_THICK + 4, h = 6);
+
+            // ── Arm attachment bosses (left side, connect to tnut_base) ──
+            for (bx = [-10, 10])
+                translate([bx, -JAW_BODY_T/2 - 8, ARM_T/2])
+                    cylinder(d = 8, h = 8);
+        }
+
+        // ── Phone pocket (open-top U channel centred in jaw) ────────────
+        // Pocket opens toward +Y (front), phone drops in from above.
+        translate([0, -JAW_BODY_T/2 - e,
+                   JAW_LIP_H])
+            cube([JAW_BODY_W - 2*JAW_WALL_T,
+                  PHONE_POCKET_D + JAW_WALL_T,
+                  JAW_BODY_H - JAW_LIP_H + e],
+                 center = [true, false, false]);
+
+        // ── Guide rod bore (M4 clearance, through both guide bosses) ────
+        translate([-JAW_BODY_W/2 - e, 0, JAW_BODY_H/2])
+            rotate([0, 90, 0])
+                cylinder(d = GUIDE_ROD_D,
+                         h = JAW_BODY_W + GUIDE_BOSS_T + 2*e);
+
+        // ── Spring pocket (coaxial with guide rod, in right boss) ────────
+        translate([JAW_BODY_W/2 + e, 0, JAW_BODY_H/2])
+            rotate([0, -90, 0])
+                cylinder(d = SPRING_OD, h = SPRING_L);
+
+        // ── M4 hex nut pocket in spring-seat wall (end-stop nut) ────────
+        translate([JAW_BODY_W/2 + GUIDE_BOSS_T + e, 0, JAW_BODY_H/2])
+            rotate([0, -90, 0])
+                cylinder(d = M4_NUT_AF / cos(30), h = M4_NUT_H + 0.5,
+                         $fn = 6);
+
+        // ── Cam pivot bore (M4 pivot, through pivot boss) ────────────────
+        translate([JAW_BODY_W/2 - e, 0, JAW_BODY_H/2 + GUIDE_BOSS_D + 4])
+            rotate([0, 90, 0])
+                cylinder(d = CAM_BORE_D, h = 6 + 2*e);
+
+        // ── Arm attachment bolt holes (M3, to tnut_base arm stubs) ──────
+        for (bx = [-10, 10])
+            translate([bx, -JAW_BODY_T/2 - 8 - e, ARM_T/2])
+                rotate([-90, 0, 0])
+                    cylinder(d = M3_D, h = 12 + 2*e);
+
+        // ── Grip pad seats (recessed Ø1.5 mm, 2 mm deep, optional) ──────
+        for (pz = [JAW_BODY_H * 0.3, JAW_BODY_H * 0.7])
+        for (px = [-PAD_W/4, PAD_W/4])
+            translate([px, -JAW_BODY_T/2 + PHONE_POCKET_D + 1, pz])
+                rotate([-90, 0, 0])
+                    cylinder(d = M2_D, h = 10);
+
+        // ── Lightening pockets (non-structural core removal) ─────────────
+        translate([0, 0, JAW_BODY_H/2])
+            cube([JAW_BODY_W - 2*JAW_WALL_T - 4,
+                  JAW_BODY_T - 2*JAW_WALL_T,
+                  JAW_BODY_H - JAW_LIP_H - 4],
+                 center = true);
+    }
+}
+
+// ============================================================
+// PART 3 — SLIDING JAW
+// ============================================================
+// Upper clamping jaw.  Slides along the M4 guide rod.
+// Spring pushes this jaw toward the phone (inward).
+// M4 hex nut on the guide rod limits maximum travel (full open).
+// Cam lever pushes on this jaw face to compress spring (release).
+//
+// Coordinate origin same convention as fixed_jaw() for assembly.
+// Jaw slides in +X direction (away from fixed jaw left wall).
+//
+// Print jaw-pocket-face down, PETG, 5 perims, 40 % infill.
+module sliding_jaw() {
+    difference() {
+        union() {
+            // ── Main jaw body ────────────────────────────────────────────
+            translate([-JAW_WALL_T, -JAW_BODY_T/2, 0])
+                cube([JAW_BODY_W/2 + JAW_WALL_T, JAW_BODY_T, JAW_BODY_H]);
+
+            // ── Front retaining lip ──────────────────────────────────────
+            translate([-JAW_WALL_T, JAW_BODY_T/2 - JAW_LIP_T, 0])
+                cube([JAW_BODY_W/2 + JAW_WALL_T, JAW_LIP_T, JAW_LIP_H]);
+
+            // ── Guide boss (carries guide rod, spring butts against face) ─
+            translate([-JAW_WALL_T - GUIDE_BOSS_T, 0, JAW_BODY_H/2])
+                rotate([0, 90, 0])
+                    cylinder(d = GUIDE_BOSS_D, h = GUIDE_BOSS_T);
+
+            // ── Cam follower ear (contacts cam lever) ────────────────────
+            translate([-JAW_WALL_T - 2, 0,
+                       JAW_BODY_H/2 + GUIDE_BOSS_D + 4])
+                cube([4, CAM_THICK + 2, CAM_THICK + 2], center = true);
+        }
+
+        // ── Phone pocket (inner face, contacts phone side) ───────────────
+        translate([-JAW_WALL_T - e, -JAW_BODY_T/2 - e, JAW_LIP_H])
+            cube([JAW_BODY_W/2 - JAW_WALL_T + e,
+                  PHONE_POCKET_D + JAW_WALL_T + 2*e,
+                  JAW_BODY_H - JAW_LIP_H + e]);
+
+        // ── Guide rod bore (M4 clearance through boss + jaw wall) ────────
+        translate([-JAW_WALL_T - GUIDE_BOSS_T - e, 0, JAW_BODY_H/2])
+            rotate([0, 90, 0])
+                cylinder(d = GUIDE_ROD_D,
+                         h = GUIDE_BOSS_T + JAW_WALL_T + 2*e);
+
+        // ── M4 nut pocket (end-stop nut, rear of guide boss) ────────────
+        translate([-JAW_WALL_T - GUIDE_BOSS_T - e, 0, JAW_BODY_H/2])
+            rotate([0, 90, 0])
+                cylinder(d = M4_NUT_AF / cos(30), h = M4_NUT_H + 1,
+                         $fn = 6);
+
+        // ── Cam follower bore (M4 pivot passes through ear) ─────────────
+        translate([-JAW_WALL_T - 2 - e, 0,
+                   JAW_BODY_H/2 + GUIDE_BOSS_D + 4])
+            rotate([0, 90, 0])
+                cylinder(d = CAM_BORE_D, h = 6 + 2*e);
+
+        // ── Grip pad seats ───────────────────────────────────────────────
+        for (pz = [JAW_BODY_H * 0.3, JAW_BODY_H * 0.7])
+        for (px = [JAW_BODY_W/8])
+            translate([px, -JAW_BODY_T/2 + PHONE_POCKET_D + 1, pz])
+                rotate([-90, 0, 0])
+                    cylinder(d = M2_D, h = 10);
+    }
+}
+
+// ============================================================
+// PART 4 — CAM LEVER (QUICK-RELEASE)
+// ============================================================
+// Eccentric cam disc + integral handle lever.
+// Rotates 90° on M4 pivot pin between CLAMPED and RELEASED states:
+//   CLAMPED  : cam small radius (CAM_R_MIN) toward jaw → spring pushes jaw
+//   RELEASED : cam large radius (CAM_R_MAX) toward jaw → compresses spring
+//               by (CAM_R_MAX - CAM_R_MIN) = 4 mm, opening jaw
+//
+// Detent ball pocket (Ø3 mm) snaps into rail-dimple for each position.
+// Handle points rearward (-Y) in clamped state for low profile.
+//
+// Print standing on cam edge (cam disc vertical), PETG, 5 perims, 40%.
+module cam_lever() {
+    cam_offset = (CAM_R_MAX - CAM_R_MIN) / 2;   // 2 mm eccentricity
+    union() {
+        difference() {
+            union() {
+                // ── Eccentric cam disc ───────────────────────────────────
+                // Offset so pivot bore is eccentric to disc profile
+                translate([cam_offset, 0, 0])
+                    cylinder(r = CAM_R_MAX, h = CAM_THICK, center = true);
+
+                // ── Lever handle arm ─────────────────────────────────────
+                hull() {
+                    translate([cam_offset, 0, 0])
+                        cylinder(r = CAM_R_MAX, h = CAM_THICK, center = true);
+                    translate([cam_offset + CAM_HANDLE_L, 0, 0])
+                        cylinder(r = CAM_HANDLE_W/2,
+                                 h = CAM_HANDLE_T, center = true);
+                }
+            }
+
+            // ── M4 pivot bore (through cam centre) ───────────────────────
+            cylinder(d = CAM_BORE_D, h = CAM_THICK + 2*e, center = true);
+
+            // ── Detent pockets (2× Ø3 mm, at 0° and 90°) ────────────────
+            // Pocket at 0° → clamped detent
+            translate([CAM_R_MAX - 2, 0, CAM_THICK/2 - 1.5])
+                cylinder(d = CAM_DETENT_D + 0.2, h = 2);
+            // Pocket at 90° → released detent
+            translate([0, CAM_R_MAX - 2, CAM_THICK/2 - 1.5])
+                cylinder(d = CAM_DETENT_D + 0.2, h = 2);
+
+            // ── Lightening recesses on cam disc face ─────────────────────
+            for (a = [0, 60, 120, 180, 240, 300])
+                translate([cam_offset + (CAM_R_MAX - 4) * cos(a),
+                           (CAM_R_MAX - 4) * sin(a), 0])
+                    cylinder(d = 4, h = CAM_THICK + 2*e, center = true);
+
+            // ── Handle grip grooves ──────────────────────────────────────
+            for (i = [0:4])
+                translate([cam_offset + 20 + i * 5, 0, 0])
+                    rotate([90, 0, 0])
+                        cylinder(d = 2.5, h = CAM_HANDLE_W + 2*e,
+                                 center = true);
+        }
+    }
+}
+
+// ============================================================
+// PART 5 — GRIP PAD (VIBRATION DAMPENING)
+// ============================================================
+// Flat pad with transverse flexure ribs that press against phone side.
+// The rib profile (thin PETG fins) provides compliance in Z (vertical)
+// absorbing vibration transmitted through the bracket.
+// Optional: print in TPU 95A for superior damping.
+// M2 bolts or adhesive-backed foam tape attach pad to jaw pocket face.
+//
+// Pad face (+Y) contacts phone.  Mounting face (-Y) bonds to jaw.
+// Ribs run parallel to Z axis (vertical).
+//
+// Print flat (mounting face down), PETG or TPU 95A, 3 perims, 20%.
+module grip_pad() {
+    union() {
+        // ── Base plate ───────────────────────────────────────────────────
+        translate([-PAD_W/2, -PAD_T, -PAD_H/2])
+            cube([PAD_W, PAD_T, PAD_H]);
+
+        // ── Flexure ribs (transverse, dampening in Z) ────────────────────
+        // RIB_COUNT ribs spaced RIB_PITCH apart, centred on pad
+        for (i = [0 : RIB_COUNT - 1]) {
+            rx = -PAD_W/2 + RIB_PITCH/2 + i * RIB_PITCH;
+            if (abs(rx) <= PAD_W/2 - RIB_W/2)   // stay within pad
+                translate([rx, 0, 0])
+                    cube([RIB_W, RIB_H, PAD_H - 4], center = true);
+        }
+
+        // ── Corner retention nubs (M2 boss for optional bolt-through) ────
+        for (px = [-PAD_W/2 + 5, PAD_W/2 - 5])
+        for (pz = [-PAD_H/2 + 5, PAD_H/2 - 5])
+            translate([px, -PAD_T/2, pz])
+                difference() {
+                    cylinder(d = 5, h = PAD_T, center = true);
+                    cylinder(d = M2_D, h = PAD_T + 2*e, center = true);
+                }
+    }
+}

chassis/prototype_baseplate.scad

@@ -65,7 +65,7 @@ CLAMP_ALIGN_D   =   4.1;   // Ø4 pin
 // D-cut bore clearance
 DCUT_CL         =  0.3;
 
-// FC mount — MAMBA F722S 30.5 × 30.5 mm M3
+// FC mount — ESP32-S3 BALANCE 30.5 × 30.5 mm M3
 FC_PITCH        = 30.5;
 FC_HOLE_D       =  3.2;
 // FC is offset toward front of plate (away from stem)
@@ -202,7 +202,7 @@ module base_plate() {
                 translate([STEM_FLANGE_BC/2, 0, -1])
                     cylinder(d=M5, h=PLATE_THICK + 2);
 
-        // ── FC mount (MAMBA F722S 30.5 × 30.5 M3) ────────────────────────
+        // ── FC mount (ESP32-S3 BALANCE 30.5 × 30.5 M3) ────────────────────────
         for (x = [FC_X_OFFSET - FC_PITCH/2, FC_X_OFFSET + FC_PITCH/2])
         for (y = [-FC_PITCH/2, FC_PITCH/2])
             translate([x, y, -1])

chassis/rover_electronics_bay.scad

@@ -11,7 +11,7 @@
 //          • Ventilation slots      — all 4 walls + lid
 //
 // Shared mounting patterns (swappable with SaltyLab):
-//   FC    : 30.5 × 30.5 mm M3 (MAMBA F722S / Pixhawk)
+//   FC    : 30.5 × 30.5 mm M3 (ESP32-S3 BALANCE / Pixhawk)
 //   Jetson: 58 × 49 mm M3    (Orin NX / Nano Devkit carrier)
 //
 // Coordinate: bay centred at origin; Z=0 = deck top face.

chassis/rplidar_mount.scad

@@ -1,76 +1,343 @@
 // ============================================================
-// rplidar_mount.scad — RPLIDAR A1M8 Anti-Vibration Ring  Rev A
-// Agent: sl-mechanical   2026-02-28
-// ============================================================
-// Flat ring sits between platform and RPLIDAR A1M8.
-// Anti-vibration isolation via 4× M3 silicone grommets
-// (same type as FC vibration mounts — Ø6 mm silicone, M3).
+// RPLIDAR A1 Mount Bracket — Issue #596
+// Agent   : sl-mechanical
+// Date    : 2026-03-14
+// Part catalogue:
+//   1. tnut_base     — 2020 T-slot rail interface plate with M5 T-nut captive pockets
+//   2. column        — hollow elevation column, 120 mm tall, 3 stiffening ribs, cable bore
+//   3. scan_platform — top plate with Ø40 mm BC M3 mounting pattern, vibration seats
+//   4. vibe_ring     — silicone FC-grommet isolation ring for scan_platform bolts
+//   5. cable_guide   — snap-on cable management clip for column body
 //
-// Bolt stack (bottom → top):
-//   M3×30 SHCS → platform (8 mm) → grommet (8 mm) →
-//   ring (4 mm) → RPLIDAR bottom (threaded M3, ~6 mm engagement)
+// BOM:
+//   2 × M5×10 BHCS + M5 T-nuts   (tnut_base to rail)
+//   4 × M3×8  SHCS                (scan_platform to RPLIDAR A1)
+//   4 × M3 silicone FC grommets Ø8.5 OD / Ø3.2 bore  (anti-vibe)
+//   4 × M3 hex nuts               (captured in scan_platform)
 //
-// RENDER options:
-//   "ring"       print-ready flat ring (default)
-//   "assembly"   ring in position on platform stub
+// Print settings (PETG):
+//   tnut_base / column / scan_platform : 5 perimeters, 40 % gyroid, no supports
+//   vibe_ring                          : 3 perimeters, 20 % gyroid, no supports
+//   cable_guide                        : 3 perimeters, 30 % gyroid, no supports
+//
+// Export commands:
+//   openscad -D 'RENDER="tnut_base"'     -o tnut_base.stl     rplidar_mount.scad
+//   openscad -D 'RENDER="column"'        -o column.stl        rplidar_mount.scad
+//   openscad -D 'RENDER="scan_platform"' -o scan_platform.stl rplidar_mount.scad
+//   openscad -D 'RENDER="vibe_ring"'     -o vibe_ring.stl     rplidar_mount.scad
+//   openscad -D 'RENDER="cable_guide"'   -o cable_guide.stl   rplidar_mount.scad
+//   openscad -D 'RENDER="assembly"'      -o assembly.png      rplidar_mount.scad
 // ============================================================
 
-RENDER = "ring";
-
-// ── RPLIDAR A1M8 ─────────────────────────────────────────────
-RPL_BODY_D  = 70.0;          // body diameter
-RPL_BC      = 58.0;          // M3 mounting bolt circle
-
-// ── Mount ring ───────────────────────────────────────────────
-RING_OD     = 82.0;          // outer diameter (RPL_BODY_D + 12 mm)
-RING_ID     = 30.0;          // inner cutout (cable / airflow)
-RING_H      =  4.0;          // ring thickness
-
-BOLT_D      =  3.3;          // M3 clearance through-hole
-GROMMET_D   =  7.0;          // silicone grommet OD (seat recess on bottom)
-GROMMET_H   =  1.0;          // seating recess depth
+// ── Render selector ─────────────────────────────────────────
+RENDER = "assembly"; // tnut_base | column | scan_platform | vibe_ring | cable_guide | assembly
 
+// ── Global constants ────────────────────────────────────────
 $fn = 64;
-e   = 0.01;
+EPS = 0.01;
 
-// ─────────────────────────────────────────────────────────────
-module rplidar_ring() {
-    difference() {
-        cylinder(d = RING_OD, h = RING_H);
+// 2020 rail
+RAIL_W       = 20.0;   // extrusion cross-section
+RAIL_H       = 20.0;
+SLOT_NECK_H  =  3.2;   // T-slot opening width
+TNUT_W       =  9.8;   // M5 T-nut width
+TNUT_H       =  5.5;   // T-nut height (depth into slot)
+TNUT_L       = 12.0;   // T-nut body length
+M5_D         =  5.2;   // M5 clearance bore
+M5_HEAD_D    =  9.5;   // M5 BHCS head diameter
+M5_HEAD_H    =  4.0;   // M5 BHCS head height
 
-        // Central cutout
-        translate([0, 0, -e])
-            cylinder(d = RING_ID, h = RING_H + 2*e);
+// Base plate
+BASE_L       = 60.0;   // length along rail axis
+BASE_W       = 30.0;   // width across rail
+BASE_T       =  8.0;   // plate thickness
+BOLT_PITCH   = 40.0;   // M5 bolt pitch along rail (centre-to-centre)
 
-        // 4× M3 clearance holes on bolt circle
-        for (a = [45, 135, 225, 315]) {
-            translate([RPL_BC/2 * cos(a), RPL_BC/2 * sin(a), -e])
-                cylinder(d = BOLT_D, h = RING_H + 2*e);
-        }
+// Elevation column
+COL_OD       = 25.0;   // column outer diameter
+COL_ID       = 17.0;   // inner bore (cable routing)
+ELEV_H       = 120.0;  // scan plane above rail top face
+COL_WALL     = (COL_OD - COL_ID) / 2;
+RIB_W        =  3.0;   // stiffening rib width
+RIB_H        =  3.5;   // rib radial height
+CABLE_SLOT_W =  8.0;   // cable entry slot width
+CABLE_SLOT_H =  5.0;   // cable entry slot height
 
-        // Grommet seating recesses — bottom face
-        for (a = [45, 135, 225, 315]) {
-            translate([RPL_BC/2 * cos(a), RPL_BC/2 * sin(a), -e])
-                cylinder(d = GROMMET_D, h = GROMMET_H + e);
-        }
+// Scan platform
+PLAT_D       = 60.0;   // platform disc diameter (clears RPLIDAR body Ø100 mm well)
+PLAT_T       =  6.0;   // platform thickness
+RPL_BC_D     = 40.0;   // RPLIDAR M3 bolt circle diameter (4 bolts at 45 °)
+RPL_BORE_D   = 36.0;   // central pass-through for scan motor cable
+M3_D         =  3.2;   // M3 clearance bore
+M3_NUT_W     =  5.5;   // M3 hex nut across-flats
+M3_NUT_H     =  2.4;   // M3 hex nut height
+GROM_OD      =  8.5;   // FC silicone grommet OD
+GROM_ID      =  3.2;   // grommet bore
+GROM_H       =  3.0;   // grommet seat depth
+CONN_SLOT_W  = 12.0;   // connector side-exit slot width
+CONN_SLOT_H  =  5.0;   // connector slot height
+
+// Vibe ring
+VRING_OD     = GROM_OD + 1.6;  // printed retainer OD
+VRING_ID     = GROM_ID + 0.3;  // pass-through with grommet seated
+VRING_T      =  2.0;            // ring flange thickness
+
+// Cable guide clip
+CLIP_W       = 14.0;
+CLIP_T       =  3.5;
+CLIP_GAP     = COL_OD + 0.4;   // snap-fit gap (slight interference)
+SNAP_T       =  1.8;
+CABLE_CH_W   =  8.0;
+CABLE_CH_H   =  5.0;
+
+// ── Utility modules ─────────────────────────────────────────
+module chamfer_cube(size, ch=1.0) {
+    // simple chamfered box (bottom edge only for printability)
+    hull() {
+        translate([ch, ch, 0])
+            cube([size[0]-2*ch, size[1]-2*ch, EPS]);
+        translate([0, 0, ch])
+            cube(size - [0, 0, ch]);
     }
 }
 
-// ─────────────────────────────────────────────────────────────
-// Render selector
-// ─────────────────────────────────────────────────────────────
-if (RENDER == "ring") {
-    rplidar_ring();
-
-} else if (RENDER == "assembly") {
-    // Platform stub
-    color("Silver", 0.5)
-        difference() {
-            cylinder(d = 90, h = 8);
-            translate([0, 0, -e]) cylinder(d = 25.4, h = 8 + 2*e);
-        }
-    // Ring floating 8 mm above (grommet gap)
-    color("SkyBlue", 0.9)
-        translate([0, 0, 8 + 8])
-            rplidar_ring();
+module hex_pocket(af, depth) {
+    // hex nut pocket (flat-to-flat af)
+    cylinder(d = af / cos(30), h = depth, $fn = 6);
 }
+
+// ── Part 1: tnut_base ───────────────────────────────────────
+module tnut_base() {
+    difference() {
+        // Body
+        union() {
+            chamfer_cube([BASE_L, BASE_W, BASE_T], ch=1.5);
+            // Column socket boss centred on plate top face
+            translate([BASE_L/2, BASE_W/2, BASE_T])
+                cylinder(d=COL_OD + 4.0, h=8.0);
+        }
+
+        // M5 bolt holes (counterbored for BHCS heads from underneath)
+        for (x = [BASE_L/2 - BOLT_PITCH/2, BASE_L/2 + BOLT_PITCH/2])
+            translate([x, BASE_W/2, -EPS]) {
+                cylinder(d=M5_D, h=BASE_T + 8.0 + 2*EPS);
+                // counterbore from bottom
+                cylinder(d=M5_HEAD_D, h=M5_HEAD_H + EPS);
+            }
+
+        // T-nut captive pockets (accessible from bottom)
+        for (x = [BASE_L/2 - BOLT_PITCH/2, BASE_L/2 + BOLT_PITCH/2])
+            translate([x - TNUT_L/2, BASE_W/2 - TNUT_W/2, BASE_T - TNUT_H])
+                cube([TNUT_L, TNUT_W, TNUT_H + EPS]);
+
+        // Column bore into boss
+        translate([BASE_L/2, BASE_W/2, BASE_T - EPS])
+            cylinder(d=COL_OD + 0.3, h=8.0 + 2*EPS);
+
+        // Cable exit slot through base (offset 5 mm from column centre)
+        translate([BASE_L/2 - CABLE_SLOT_W/2, BASE_W/2 + COL_OD/4, -EPS])
+            cube([CABLE_SLOT_W, CABLE_SLOT_H, BASE_T + 8.0 + 2*EPS]);
+
+        // Weight relief pockets on underside
+        for (x = [BASE_L/2 - BOLT_PITCH/2 + 10, BASE_L/2 + BOLT_PITCH/2 - 10])
+            for (y = [7, BASE_W - 7])
+                translate([x - 5, y - 5, -EPS])
+                    cube([10, 10, BASE_T/2]);
+    }
+}
+
+// ── Part 2: column ──────────────────────────────────────────
+module column() {
+    // Actual column height: ELEV_H minus base boss engagement (8 mm) and platform seating (6 mm)
+    col_h = ELEV_H - 8.0 - PLAT_T;
+
+    difference() {
+        union() {
+            // Hollow tube
+            cylinder(d=COL_OD, h=col_h);
+
+            // Three 120°-spaced stiffening ribs along full height
+            for (a = [0, 120, 240])
+                rotate([0, 0, a])
+                    translate([COL_OD/2 - EPS, -RIB_W/2, 0])
+                        cube([RIB_H, RIB_W, col_h]);
+
+            // Bottom spigot (fits into base boss bore)
+            translate([0, 0, -6.0])
+                cylinder(d=COL_OD - 0.4, h=6.0 + EPS);
+
+            // Top spigot (seats into scan_platform recess)
+            translate([0, 0, col_h - EPS])
+                cylinder(d=COL_OD - 0.4, h=6.0);
+        }
+
+        // Inner cable bore
+        translate([0, 0, -6.0 - EPS])
+            cylinder(d=COL_ID, h=col_h + 12.0 + 2*EPS);
+
+        // Cable entry slot at bottom (aligns with base slot)
+        translate([-CABLE_SLOT_W/2, -COL_OD/2 - EPS, 2.0])
+            cube([CABLE_SLOT_W, CABLE_SLOT_H + EPS, CABLE_SLOT_H]);
+
+        // Cable exit slot at top (90° rotated for tidy routing)
+        rotate([0, 0, 90])
+            translate([-CABLE_SLOT_W/2, -COL_OD/2 - EPS, col_h - CABLE_SLOT_H - 4.0])
+                cube([CABLE_SLOT_W, CABLE_SLOT_H + EPS, CABLE_SLOT_H]);
+
+        // Cable clip snap groove (at mid-height)
+        translate([0, 0, col_h / 2])
+            difference() {
+                cylinder(d=COL_OD + 2*RIB_H + 0.8, h=4.0, center=true);
+                cylinder(d=COL_OD - 0.2, h=4.0 + 2*EPS, center=true);
+            }
+    }
+}
+
+// ── Part 3: scan_platform ───────────────────────────────────
+module scan_platform() {
+    difference() {
+        union() {
+            // Main disc
+            cylinder(d=PLAT_D, h=PLAT_T);
+
+            // Rim lip for stiffness
+            translate([0, 0, PLAT_T])
+                difference() {
+                    cylinder(d=PLAT_D, h=2.0);
+                    cylinder(d=PLAT_D - 4.0, h=2.0 + EPS);
+                }
+        }
+
+        // Central cable pass-through
+        translate([0, 0, -EPS])
+            cylinder(d=RPL_BORE_D, h=PLAT_T + 4.0);
+
+        // Column spigot socket (bottom recess)
+        translate([0, 0, -EPS])
+            cylinder(d=COL_OD - 0.4 + 0.4, h=6.0);
+
+        // RPLIDAR M3 mounting holes — 4× on Ø40 BC at 45°/135°/225°/315°
+        for (a = [45, 135, 225, 315])
+            rotate([0, 0, a])
+                translate([RPL_BC_D/2, 0, -EPS]) {
+                    // Through bore
+                    cylinder(d=M3_D, h=PLAT_T + 2*EPS);
+                    // Grommet seat (countersunk from top)
+                    translate([0, 0, PLAT_T - GROM_H])
+                        cylinder(d=GROM_OD + 0.3, h=GROM_H + EPS);
+                    // Captured M3 hex nut pocket (from bottom)
+                    translate([0, 0, 1.5])
+                        hex_pocket(M3_NUT_W + 0.3, M3_NUT_H + 0.2);
+                }
+
+        // Connector side-exit slots (2× opposing, at 0° and 180°)
+        for (a = [0, 180])
+            rotate([0, 0, a])
+                translate([-CONN_SLOT_W/2, PLAT_D/2 - CONN_SLOT_H, -EPS])
+                    cube([CONN_SLOT_W, CONN_SLOT_H + EPS, PLAT_T + 2*EPS]);
+
+        // Weight relief pockets (2× lateral)
+        for (a = [90, 270])
+            rotate([0, 0, a])
+                translate([-10, 15, 1.5])
+                    cube([20, 8, PLAT_T - 3.0]);
+    }
+}
+
+// ── Part 4: vibe_ring ───────────────────────────────────────
+// Printed silicone-grommet retainer ring — press-fits over M3 bolt with grommet seated
+module vibe_ring() {
+    difference() {
+        union() {
+            cylinder(d=VRING_OD, h=VRING_T + GROM_H);
+            // Flange
+            cylinder(d=VRING_OD + 2.0, h=VRING_T);
+        }
+        // Bore
+        translate([0, 0, -EPS])
+            cylinder(d=VRING_ID, h=VRING_T + GROM_H + 2*EPS);
+    }
+}
+
+// ── Part 5: cable_guide ─────────────────────────────────────
+// Snap-on cable clip for column mid-section
+module cable_guide() {
+    arm_t = SNAP_T;
+    gap   = CLIP_GAP;
+
+    difference() {
+        union() {
+            // Saddle body (U-shape wrapping column)
+            difference() {
+                cylinder(d=gap + 2*CLIP_T, h=CLIP_W);
+                translate([0, 0, -EPS])
+                    cylinder(d=gap, h=CLIP_W + 2*EPS);
+                // Open front slot for snap insertion
+                translate([-gap/2, 0, -EPS])
+                    cube([gap, gap/2 + CLIP_T + EPS, CLIP_W + 2*EPS]);
+            }
+
+            // Snap arms
+            for (s = [-1, 1])
+                translate([s*(gap/2 - arm_t), 0, 0])
+                    mirror([s < 0 ? 1 : 0, 0, 0])
+                        translate([0, -arm_t/2, 0])
+                            cube([arm_t + 1.5, arm_t, CLIP_W]);
+
+            // Cable channel bracket (side-mounted)
+            translate([gap/2 + CLIP_T, -(CABLE_CH_W/2 + CLIP_T), 0])
+                cube([CLIP_T + CABLE_CH_H, CABLE_CH_W + 2*CLIP_T, CLIP_W]);
+        }
+
+        // Cable channel cutout
+        translate([gap/2 + CLIP_T + CLIP_T - EPS, -CABLE_CH_W/2, -EPS])
+            cube([CABLE_CH_H + EPS, CABLE_CH_W, CLIP_W + 2*EPS]);
+
+        // Snap tip undercut (both arms)
+        for (s = [-1, 1])
+            translate([s*(gap/2 + CLIP_T + 1.0), -arm_t, -EPS])
+                rotate([0, 0, s*30])
+                    cube([2, arm_t*2, CLIP_W + 2*EPS]);
+    }
+}
+
+// ── Assembly / render dispatch ───────────────────────────────
+module assembly() {
+    // tnut_base at origin
+    color("SteelBlue")
+        tnut_base();
+
+    // column rising from base boss
+    color("DodgerBlue")
+        translate([BASE_L/2, BASE_W/2, BASE_T + 8.0 - 6.0])
+            column();
+
+    // scan_platform at top of column
+    col_h_actual = ELEV_H - 8.0 - PLAT_T;
+    color("CornflowerBlue")
+        translate([BASE_L/2, BASE_W/2, BASE_T + 8.0 - 6.0 + col_h_actual + 6.0 - EPS])
+            scan_platform();
+
+    // vibe rings (4×) seated in platform holes
+    for (a = [45, 135, 225, 315])
+        color("Gray", 0.7)
+            translate([BASE_L/2, BASE_W/2,
+                       BASE_T + 8.0 - 6.0 + col_h_actual + 6.0 + PLAT_T - GROM_H])
+                rotate([0, 0, a])
+                    translate([RPL_BC_D/2, 0, 0])
+                        vibe_ring();
+
+    // cable_guide clipped at column mid-height
+    color("LightSteelBlue")
+        translate([BASE_L/2, BASE_W/2,
+                   BASE_T + 8.0 - 6.0 + (ELEV_H - 8.0 - PLAT_T)/2 - CLIP_W/2])
+            cable_guide();
+}
+
+// ── Dispatch ────────────────────────────────────────────────
+if      (RENDER == "tnut_base")     tnut_base();
+else if (RENDER == "column")        column();
+else if (RENDER == "scan_platform") scan_platform();
+else if (RENDER == "vibe_ring")     vibe_ring();
+else if (RENDER == "cable_guide")   cable_guide();
+else                                assembly();

chassis/saltyrover_chassis_r2.scad

@@ -17,7 +17,7 @@
 //   • Weight target: <2 kg frame (excl. motors/electronics)
 //
 // Shared SaltyLab patterns (swappable electronics):
-//   FC  : 30.5 × 30.5 mm M3  (MAMBA F722S / Pixhawk)
+//   FC  : 30.5 × 30.5 mm M3  (ESP32-S3 BALANCE / Pixhawk)
 //   Jetson: 58 × 49 mm M3    (Orin NX / Nano carrier board)
 //   Stem  : Ø25 mm bore      (sensor head unchanged)
 //
@@ -87,7 +87,7 @@ STEM_COLLAR_OD = 50.0;
 STEM_COLLAR_H  = 20.0;   // raised boss height above deck top
 STEM_FLANGE_BC = 40.0;   // 4× M4 bolt circle for stem adapter
 
-// ── FC mount — MAMBA F722S / Pixhawk (30.5 × 30.5 mm M3) ────────────────────
+// ── FC mount — ESP32-S3 BALANCE / Pixhawk (30.5 × 30.5 mm M3) ────────────────────
 // Shared with SaltyLab — swappable electronics
 FC_PITCH    = 30.5;
 FC_HOLE_D   =  3.2;

chassis/uwb_anchor_mount.scad

@@ -1,275 +1,341 @@
 // ============================================================
-// uwb_anchor_mount.scad — Stem-Mounted UWB Anchor  Rev A
-// Agent: sl-mechanical   2026-03-01
-// Closes issues #57, #62
+// uwb_anchor_mount.scad — Wall/Ceiling UWB Anchor Mount Bracket
+// Issue: #564  Agent: sl-mechanical  Date: 2026-03-14
+// (supersedes Rev A stem-collar mount — see git history)
 // ============================================================
-// Clamp-on bracket for 2× MaUWB ESP32-S3 anchor modules on
-// SaltyBot 25 mm OD vertical stem.
-// Anchors spaced ANCHOR_SPACING = 250 mm apart.
 //
-// Features:
-//   • Split D-collar with M4 clamping bolts + M4 set screw
-//   • Anti-rotation flat tab that keys against a small pin
-//     OR printed key tab that registers on the stem flat (if stem
-//     has a ground flat) — see ANTI_ROT_MODE parameter
-//   • Module bracket: faces outward, tilted 10° from vertical
-//     so antenna clears stem and faces horizon
-//   • USB cable channel (power from Orin via USB-A) on collar
-//   • Tool-free capture: M4 thumbscrews (slot-head, hand-tighten)
-//   • UWB antenna area: NO material within 10 mm of PCB top face
+// Parametric wall or ceiling mount bracket for ESP32 UWB Pro anchor.
+// Designed for fixed-infrastructure deployment: anchors screw into
+// wall or ceiling drywall/timber with standard M4 or #6 wood screws,
+// at a user-defined tilt angle so the UWB antenna faces the desired
+// coverage zone.
 //
-// Components per mount:
-//   2× collar_half        print in PLA/PETG, flat-face-down
-//   1× module_bracket     print in PLA/PETG, flat-face-down
+// Architecture:
+//   Wall base    -> flat backplate with 2x screw holes (wall or ceiling)
+//   Tilt knuckle -> single-axis articulating joint; 15deg detent steps
+//                   locked with M3 nyloc bolt; range 0-90deg
+//   Anchor cradle-> U-cradle holding ESP32 UWB Pro PCB on M2.5 standoffs
+//   USB-C channel-> routed groove on tilt arm + exit slot in cradle back wall
+//   Label slot   -> rear window slot for printed anchor-ID card strip
+//
+// Part catalogue:
+//   Part 1 -- wall_base()       Backplate + 2-ear pivot block + detent arc
+//   Part 2 -- tilt_arm()        Pivoting arm with knuckle + cradle stub
+//   Part 3 -- anchor_cradle()   PCB cradle, standoffs, USB-C slot, label window
+//   Part 4 -- cable_clip()      Snap-on USB-C cable guide for tilt arm
+//   Part 5 -- assembly_preview()
+//
+// Hardware BOM:
+//   2x M4 x 30mm wood screws (or #6 drywall screws)  wall fasteners
+//   1x M3 x 20mm SHCS + M3 nyloc nut                 tilt pivot bolt
+//   4x M2.5 x 8mm SHCS                               PCB-to-cradle
+//   4x M2.5 hex nuts                                  captured in standoffs
+//   1x USB-C cable                                    anchor power
+//
+// ESP32 UWB Pro interface (verify with calipers):
+//   PCB size       : UWB_L x UWB_W x UWB_H  (55 x 28 x 10 mm default)
+//   Mounting holes : M2.5, 4x corners on UWB_HOLE_X x UWB_HOLE_Y pattern
+//   USB-C port     : centred on short edge, UWB_USBC_W x UWB_USBC_H
+//   Antenna area   : top face rear half -- 10mm keep-out of bracket material
+//
+// Tilt angles (15deg detent steps, set TILT_DEG before export):
+//   0deg  -> horizontal face-up   (ceiling, antenna faces down)
+//   30deg -> 30deg downward tilt  (wall near ceiling)  [default]
+//   45deg -> diagonal             (wall mid-height)
+//   90deg -> vertical face-out    (wall, antenna faces forward)
 //
 // RENDER options:
-//   "assembly"       single mount assembled (default)
-//   "collar_front"   front collar half for slicing (×2 per mount × 2 mounts = 4)
-//   "collar_rear"    rear collar half
-//   "bracket"        module bracket (×2 mounts)
-//   "pair"           both mounts on 350 mm stem section
+//   "assembly"           full assembly at TILT_DEG (default)
+//   "wall_base_stl"      Part 1
+//   "tilt_arm_stl"       Part 2
+//   "anchor_cradle_stl"  Part 3
+//   "cable_clip_stl"     Part 4
+//
+// Export commands:
+//   openscad uwb_anchor_mount.scad -D 'RENDER="wall_base_stl"'     -o uwb_wall_base.stl
+//   openscad uwb_anchor_mount.scad -D 'RENDER="tilt_arm_stl"'      -o uwb_tilt_arm.stl
+//   openscad uwb_anchor_mount.scad -D 'RENDER="anchor_cradle_stl"' -o uwb_anchor_cradle.stl
+//   openscad uwb_anchor_mount.scad -D 'RENDER="cable_clip_stl"'    -o uwb_cable_clip.stl
 // ============================================================
 
+$fn  = 64;
+e    = 0.01;
+
+// -- Tilt angle (override per anchor, 0-90deg, 15deg steps) ------------------
+TILT_DEG = 30;
+
+// -- ESP32 UWB Pro PCB dimensions (verify with calipers) ---------------------
+UWB_L         = 55.0;
+UWB_W         = 28.0;
+UWB_H         = 10.0;
+UWB_HOLE_X    = 47.5;
+UWB_HOLE_Y    = 21.0;
+UWB_USBC_W    =  9.5;
+UWB_USBC_H    =  4.0;
+UWB_ANTENNA_L = 20.0;
+
+// -- Wall base geometry -------------------------------------------------------
+BASE_W         = 60.0;
+BASE_H         = 50.0;
+BASE_T         =  5.0;
+BASE_SCREW_D   =  4.5;
+BASE_SCREW_HD  =  8.5;
+BASE_SCREW_HH  =  3.5;
+BASE_SCREW_SPC = 35.0;
+KNUCKLE_T      = BASE_T + 4.0;
+
+// -- Tilt arm geometry --------------------------------------------------------
+ARM_W         = 12.0;
+ARM_T         =  5.0;
+ARM_L         = 35.0;
+PIVOT_D       =  3.3;
+PIVOT_NUT_AF  =  5.5;
+PIVOT_NUT_H   =  2.4;
+DETENT_D      =  3.2;
+DETENT_R      =  8.0;
+
+// -- Anchor cradle geometry ---------------------------------------------------
+CRADLE_WALL_T  =  3.5;
+CRADLE_BACK_T  =  4.0;
+CRADLE_FLOOR_T =  3.0;
+CRADLE_LIP_H   =  4.0;
+CRADLE_LIP_T   =  2.5;
+STANDOFF_H     =  3.0;
+STANDOFF_OD    =  5.5;
+LABEL_W        = UWB_L - 4.0;
+LABEL_H        = UWB_W * 0.55;
+LABEL_T        =  1.2;
+
+// -- USB-C routing ------------------------------------------------------------
+USBC_CHAN_W   = 11.0;
+USBC_CHAN_H   =  7.0;
+
+// -- Cable clip ---------------------------------------------------------------
+CLIP_CABLE_D  =  4.5;
+CLIP_T        =  2.0;
+CLIP_BODY_W   = 16.0;
+CLIP_BODY_H   = 10.0;
+
+// -- Fasteners ----------------------------------------------------------------
+M2P5_D    = 2.7;
+M3_D      = 3.3;
+M3_NUT_AF = 5.5;
+M3_NUT_H  = 2.4;
+
+// ============================================================
+// RENDER DISPATCH
+// ============================================================
 RENDER = "assembly";
 
-// ── ⚠ Verify with calipers ───────────────────────────────────
-MAWB_L      = 50.0;   // PCB length
-MAWB_W      = 25.0;   // PCB width
-MAWB_H      = 10.0;   // PCB + components
-MAWB_HOLE_X = 43.0;   // M2 mounting hole X span
-MAWB_HOLE_Y = 20.0;   // M2 mounting hole Y span
-M2_D        =  2.2;   // M2 clearance
+if      (RENDER == "assembly")           assembly_preview();
+else if (RENDER == "wall_base_stl")      wall_base();
+else if (RENDER == "tilt_arm_stl")       tilt_arm();
+else if (RENDER == "anchor_cradle_stl")  anchor_cradle();
+else if (RENDER == "cable_clip_stl")     cable_clip();
 
-// ── Stem ─────────────────────────────────────────────────────
-STEM_OD     = 25.0;
-STEM_BORE   = 25.4;   // +0.4 clearance
-WALL        =  2.0;   // wall thickness (used in thumbscrew recess)
+// ============================================================
+// ASSEMBLY PREVIEW
+// ============================================================
+module assembly_preview() {
+    %color("Wheat", 0.22)
+        translate([-BASE_W/2, -10, -BASE_H/2])
+            cube([BASE_W, 10, BASE_H + 40]);
+    color("OliveDrab", 0.85)  wall_base();
+    color("SteelBlue", 0.85)
+        translate([0, KNUCKLE_T, 0]) rotate([TILT_DEG,0,0]) tilt_arm();
+    color("DarkSlateGray", 0.85)
+        translate([0, KNUCKLE_T, 0]) rotate([TILT_DEG,0,0])
+            translate([0, ARM_T, ARM_L]) anchor_cradle();
+    %color("ForestGreen", 0.38)
+        translate([0, KNUCKLE_T, 0]) rotate([TILT_DEG,0,0])
+            translate([-UWB_L/2, ARM_T+CRADLE_BACK_T,
+                       ARM_L+CRADLE_FLOOR_T+STANDOFF_H])
+                cube([UWB_L, UWB_W, UWB_H]);
+    color("DimGray", 0.70)
+        translate([ARM_W/2, KNUCKLE_T, 0]) rotate([TILT_DEG,0,0])
+            translate([0, ARM_T+e, ARM_L/2]) rotate([0,-90,90]) cable_clip();
+}
 
-// ── Collar ───────────────────────────────────────────────────
-COL_OD      = 52.0;
-COL_H       = 30.0;   // taller than sensor-head collar for rigidity
-COL_BOLT_X  = 19.0;   // M4 bolt CL from stem axis
-COL_BOLT_D  =  4.5;   // M4 clearance
-THUMB_HEAD_D=  8.0;   // M4 thumbscrew head OD (slot for access)
-COL_NUT_W   =  7.0;   // M4 hex nut A/F
-COL_NUT_H   =  3.4;
-
-// Anti-rotation flat tab: a 3 mm wall tab that protrudes radially
-// and bears against the bracket arm, preventing axial rotation
-// without needing a stem flat.
-ANTI_ROT_T  =  3.0;   // tab thickness (radial)
-ANTI_ROT_W  =  8.0;   // tab width (tangential)
-ANTI_ROT_Z  =  4.0;   // distance from collar base
-
-// USB cable channel: groove on collar outer surface, runs Z direction
-// Cable routes from anchor module down to base
-USB_CHAN_W  =  9.0;   // channel width (fits USB-A cable Ø6 mm)
-USB_CHAN_D  =  5.0;   // channel depth
-
-// ── Module bracket ───────────────────────────────────────────
-ARM_L       = 20.0;   // arm length from collar OD to bracket face
-ARM_W       = MAWB_W + 6.0; // bracket width (Y, includes side walls)
-ARM_H       =  6.0;   // arm thickness (Z)
-BRKT_TILT   = 10.0;   // tilt outward from vertical (antenna faces horizon)
-
-BRKT_BACK_T =  3.0;   // bracket back wall (module sits against this)
-BRKT_SIDE_T =  2.0;   // bracket side walls
-
-M2_STNDFF   =  3.0;   // M2 standoff height
-M2_STNDFF_OD=  4.5;
-
-// USB port access notch in bracket side wall (8×5 mm)
-USB_NOTCH_W = 10.0;
-USB_NOTCH_H =  7.0;
-
-// ── Spacing ───────────────────────────────────────────────────
-ANCHOR_SPACING = 250.0;  // centre-to-centre Z separation
-
-$fn = 64;
-e   = 0.01;
-
-// ─────────────────────────────────────────────────────────────
-// collar_half(side)
-//   split at Y=0 plane.  Bracket arm on front (+Y) half.
-//   Print flat-face-down.
-// ─────────────────────────────────────────────────────────────
-module collar_half(side = "front") {
-    y_front = (side == "front");
+// ============================================================
+// PART 1 -- WALL BASE
+// ============================================================
+// Flat backplate, 2x countersunk M4/#6 wood screws on 35mm centres.
+// Two pivot ears straddle the tilt arm; M3 pivot bolt through both.
+// Detent arc on +X ear inner face: 7 notches at 15deg steps (0-90deg).
+// Shallow rear recess for installation-zone label strip.
+// Same part for wall mount and ceiling mount.
+//
+// Print: backplate flat on bed, PETG, 5 perims, 40% gyroid.
+module wall_base() {
+    ear_h   = ARM_W + 3.0;
+    ear_t   = 6.0;
+    ear_sep = ARM_W + 1.0;
 
     difference() {
         union() {
-            // D-shaped body
-            intersection() {
-                cylinder(d=COL_OD, h=COL_H);
-                translate([-COL_OD/2, y_front ? 0 : -COL_OD/2, 0])
-                    cube([COL_OD, COL_OD/2, COL_H]);
-            }
-
-            // Anti-rotation tab (front half only, at +X side)
-            if (y_front) {
-                translate([COL_OD/2, -ANTI_ROT_W/2, ANTI_ROT_Z])
-                    cube([ANTI_ROT_T, ANTI_ROT_W,
-                          COL_H - ANTI_ROT_Z - 4]);
-            }
-
-            // Bracket arm attachment boss (front half only, top centre)
-            if (y_front) {
-                translate([-ARM_W/2, COL_OD/2, COL_H * 0.3])
-                    cube([ARM_W, ARM_L, COL_H * 0.4]);
-            }
+            translate([-BASE_W/2, -BASE_T, -BASE_H/2])
+                cube([BASE_W, BASE_T, BASE_H]);
+            for (ex = [-(ear_sep/2 + ear_t), ear_sep/2])
+                translate([ex, -BASE_T+e, -ear_h/2])
+                    cube([ear_t, KNUCKLE_T+e, ear_h]);
+            for (ex = [-(ear_sep/2 + ear_t), ear_sep/2])
+                hull() {
+                    translate([ex, -BASE_T, -ear_h/4])
+                        cube([ear_t, BASE_T-1, ear_h/2]);
+                    translate([ex + (ex<0 ? ear_t*0.5 : 0), -BASE_T, -ear_h/6])
+                        cube([ear_t*0.5, 1, ear_h/3]);
+                }
         }
-
-        // ── Stem bore ─────────────────────────────────────────
-        translate([0,0,-e])
-            cylinder(d=STEM_BORE, h=COL_H + 2*e);
-
-        // ── M4 clamping bolt holes (Y direction) ──────────────
-        for (bx=[-COL_BOLT_X, COL_BOLT_X]) {
-            translate([bx, y_front ? COL_OD/2 : 0, COL_H/2])
-                rotate([90,0,0])
-                    cylinder(d=COL_BOLT_D, h=COL_OD/2 + e);
-            // Thumbscrew head recess on outer face (front only — access side)
-            if (y_front) {
-                translate([bx, COL_OD/2 - WALL, COL_H/2])
-                    rotate([90,0,0])
-                        cylinder(d=THUMB_HEAD_D, h=8 + e);
-            }
-        }
-
-        // ── M4 hex nut pockets (rear half) ────────────────────
-        if (!y_front) {
-            for (bx=[-COL_BOLT_X, COL_BOLT_X]) {
-                translate([bx, -(COL_OD/4 + e), COL_H/2])
-                    rotate([90,0,0])
-                        cylinder(d=COL_NUT_W/cos(30), h=COL_NUT_H + e,
-                                 $fn=6);
-            }
-        }
-
-        // ── Set screw (height lock, front half) ───────────────
-        if (y_front) {
-            translate([0, COL_OD/2, COL_H * 0.8])
-                rotate([90,0,0])
-                    cylinder(d=COL_BOLT_D,
-                             h=COL_OD/2 - STEM_BORE/2 + e);
-        }
-
-        // ── USB cable routing channel (rear half, −X side) ────
-        if (!y_front) {
-            translate([-COL_OD/2, -USB_CHAN_W/2, -e])
-                cube([USB_CHAN_D, USB_CHAN_W, COL_H + 2*e]);
-        }
-
-        // ── M4 hole through arm boss (Z direction, for bracket bolt) ─
-        if (y_front) {
-            for (dx=[-ARM_W/4, ARM_W/4])
-                translate([dx, COL_OD/2 + ARM_L/2, COL_H * 0.35])
-                    cylinder(d=COL_BOLT_D, h=COL_H * 0.35 + e);
+        for (sz = [-BASE_SCREW_SPC/2, BASE_SCREW_SPC/2]) {
+            translate([0, -BASE_T-e, sz]) rotate([-90,0,0])
+                cylinder(d=BASE_SCREW_D, h=BASE_T+2*e);
+            translate([0, -BASE_T-e, sz]) rotate([-90,0,0])
+                cylinder(d1=BASE_SCREW_HD, d2=BASE_SCREW_D, h=BASE_SCREW_HH+e);
         }
+        translate([-(ear_sep/2+ear_t+e), KNUCKLE_T*0.55, 0])
+            rotate([0,90,0]) cylinder(d=PIVOT_D, h=ear_sep+2*ear_t+2*e);
+        translate([ear_sep/2+ear_t-PIVOT_NUT_H-0.4, KNUCKLE_T*0.55, 0])
+            rotate([0,90,0])
+                cylinder(d=PIVOT_NUT_AF/cos(30), h=PIVOT_NUT_H+0.5, $fn=6);
+        for (da = [0 : 15 : 90])
+            translate([ear_sep/2-e,
+                       KNUCKLE_T*0.55 + DETENT_R*sin(da),
+                       DETENT_R*cos(da)])
+                rotate([0,90,0]) cylinder(d=DETENT_D, h=ear_t*0.45+e);
+        translate([0, -BASE_T-e, 0]) rotate([-90,0,0])
+            cube([BASE_W-12, BASE_H-16, 1.6], center=true);
+        translate([0, -BASE_T+1.5, 0])
+            cube([BASE_W-14, BASE_T-3, BASE_H-20], center=true);
     }
 }
 
-// ─────────────────────────────────────────────────────────────
-// module_bracket()
-//   Bolts to collar arm boss. Holds MaUWB PCB facing outward.
-//   Tilted BRKT_TILT° from vertical — antenna clears stem.
-//   Print flat-face-down (back wall on bed).
-// ─────────────────────────────────────────────────────────────
-module module_bracket() {
-    bk = BRKT_BACK_T;
-    sd = BRKT_SIDE_T;
+// ============================================================
+// PART 2 -- TILT ARM
+// ============================================================
+// Pivoting arm linking wall_base ears to anchor_cradle.
+// Knuckle (Z=0): M3 pivot bore + spring-plunger detent pocket (3mm).
+// Cradle end (Z=ARM_L): 2x M3 bolt attachment stub.
+// USB-C cable channel groove on outer +Y face, full arm length.
+//
+// Print: knuckle face flat on bed, PETG, 5 perims, 40% gyroid.
+module tilt_arm() {
+    total_h = ARM_L + 10;
+    difference() {
+        union() {
+            translate([-ARM_W/2, 0, 0]) cube([ARM_W, ARM_T, total_h]);
+            translate([0, ARM_T/2, 0]) rotate([90,0,0])
+                cylinder(d=ARM_W, h=ARM_T, center=true);
+            translate([-ARM_W/2, 0, ARM_L])
+                cube([ARM_W, ARM_T+CRADLE_BACK_T, ARM_T]);
+        }
+        translate([-ARM_W/2-e, ARM_T/2, 0]) rotate([0,90,0])
+            cylinder(d=PIVOT_D, h=ARM_W+2*e);
+        translate([0, ARM_T+e, 0]) rotate([90,0,0])
+            cylinder(d=3.2, h=4+e);
+        translate([-USBC_CHAN_W/2, ARM_T-e, ARM_T+4])
+            cube([USBC_CHAN_W, USBC_CHAN_H, ARM_L-ARM_T-8]);
+        for (bx = [-ARM_W/4, ARM_W/4])
+            translate([bx, ARM_T/2, ARM_L+ARM_T/2]) rotate([90,0,0])
+                cylinder(d=M3_D, h=ARM_T+CRADLE_BACK_T+2*e);
+        for (bx = [-ARM_W/4, ARM_W/4])
+            translate([bx, ARM_T/2, ARM_L+ARM_T/2]) rotate([-90,0,0])
+                cylinder(d=M3_NUT_AF/cos(30), h=M3_NUT_H+0.5, $fn=6);
+        translate([0, ARM_T/2, ARM_L/2])
+            cube([ARM_W-4, ARM_T-2, ARM_L-18], center=true);
+    }
+}
+
+// ============================================================
+// PART 3 -- ANCHOR CRADLE
+// ============================================================
+// Open-front U-cradle for ESP32 UWB Pro PCB.
+// 4x M2.5 standoffs on UWB_HOLE_X x UWB_HOLE_Y pattern.
+// Back wall: USB-C exit slot + routing groove, label card slot,
+//            antenna keep-out cutout (material removed above antenna area).
+// Front retaining lip prevents PCB sliding out.
+// Two attachment tabs bolt to tilt_arm cradle stub via M3.
+//
+// Label card slot: insert paper/laminate strip to ID this anchor
+// (e.g. "UWB-A3 NE-CORNER"), accessible from open cradle end.
+//
+// Print: back wall flat on bed, PETG, 5 perims, 40% gyroid.
+module anchor_cradle() {
+    outer_l  = UWB_L + 2*CRADLE_WALL_T;
+    outer_w  = UWB_W + CRADLE_FLOOR_T;
+    pcb_z    = CRADLE_FLOOR_T + STANDOFF_H;
+    total_z  = pcb_z + UWB_H + 2;
 
     difference() {
         union() {
-            // ── Back wall (mounts to collar arm boss) ─────────
-            cube([ARM_W, bk, MAWB_H + M2_STNDFF + 6]);
-
-            // ── Side walls ────────────────────────────────────
-            for (sx=[0, ARM_W - sd])
-                translate([sx, bk, 0])
-                    cube([sd, MAWB_L + 2, MAWB_H + M2_STNDFF + 6]);
-
-            // ── M2 standoff posts (PCB mounts to these) ───────
-            for (hx=[0, MAWB_HOLE_X], hy=[0, MAWB_HOLE_Y])
-                translate([(ARM_W - MAWB_HOLE_X)/2 + hx,
-                           bk + (MAWB_L - MAWB_HOLE_Y)/2 + hy,
-                           0])
-                    cylinder(d=M2_STNDFF_OD, h=M2_STNDFF);
+            translate([-outer_l/2, 0, 0]) cube([outer_l, outer_w, total_z]);
+            translate([-outer_l/2, outer_w-CRADLE_LIP_T, 0])
+                cube([outer_l, CRADLE_LIP_T, CRADLE_LIP_H]);
+            for (tx = [-ARM_W/4, ARM_W/4])
+                translate([tx-4, -CRADLE_BACK_T, 0])
+                    cube([8, CRADLE_BACK_T+1, total_z]);
         }
+        translate([-UWB_L/2, 0, pcb_z]) cube([UWB_L, UWB_W+1, UWB_H+4]);
+        translate([0, -CRADLE_BACK_T-e, pcb_z+UWB_H/2-UWB_USBC_H/2])
+            cube([UWB_USBC_W+2, CRADLE_BACK_T+2*e, UWB_USBC_H+2],
+                 center=[true,false,false]);
+        translate([0, -CRADLE_BACK_T-e, -e])
+            cube([USBC_CHAN_W, USBC_CHAN_H, pcb_z+UWB_H/2+USBC_CHAN_H],
+                 center=[true,false,false]);
+        translate([0, -CRADLE_BACK_T-e, pcb_z+UWB_H/2])
+            cube([LABEL_W, LABEL_T+0.3, LABEL_H], center=[true,false,false]);
+        translate([0, -e, pcb_z+UWB_H-UWB_ANTENNA_L])
+            cube([UWB_L-4, CRADLE_BACK_T+2*e, UWB_ANTENNA_L+4],
+                 center=[true,false,false]);
+        for (tx = [-ARM_W/4, ARM_W/4])
+            translate([tx, ARM_T/2-CRADLE_BACK_T, total_z/2])
+                rotate([-90,0,0])
+                    cylinder(d=M3_D, h=ARM_T+CRADLE_BACK_T+2*e);
+        for (side_x = [-outer_l/2-e, outer_l/2-CRADLE_WALL_T-e])
+            translate([side_x, 2, pcb_z+2])
+                cube([CRADLE_WALL_T+2*e, UWB_W-4, UWB_H-4]);
+    }
+    for (hx = [-UWB_HOLE_X/2, UWB_HOLE_X/2])
+    for (hy = [(outer_w-UWB_W)/2 + (UWB_W-UWB_HOLE_Y)/2,
+               (outer_w-UWB_W)/2 + (UWB_W-UWB_HOLE_Y)/2 + UWB_HOLE_Y])
+        difference() {
+            translate([hx, hy, CRADLE_FLOOR_T-e])
+                cylinder(d=STANDOFF_OD, h=STANDOFF_H+e);
+            translate([hx, hy, CRADLE_FLOOR_T-2*e])
+                cylinder(d=M2P5_D, h=STANDOFF_H+4);
+        }
+}
 
-        // ── M2 bores through standoffs ────────────────────────
-        for (hx=[0, MAWB_HOLE_X], hy=[0, MAWB_HOLE_Y])
-            translate([(ARM_W - MAWB_HOLE_X)/2 + hx,
-                       bk + (MAWB_L - MAWB_HOLE_Y)/2 + hy,
-                       -e])
-                cylinder(d=M2_D, h=M2_STNDFF + e);
-
-        // ── Antenna clearance cutout in back wall ─────────────
-        // Open slot near top of back wall so antenna is unobstructed
-        translate([sd, -e, M2_STNDFF + 2])
-            cube([ARM_W - 2*sd, bk + 2*e, MAWB_H]);
-
-        // ── USB port access notch on one side wall ────────────
-        translate([-e, bk + 2, M2_STNDFF - 1])
-            cube([sd + 2*e, USB_NOTCH_W, USB_NOTCH_H]);
-
-        // ── Mounting holes to collar arm boss (×2) ────────────
-        for (dx=[-ARM_W/4, ARM_W/4])
-            translate([ARM_W/2 + dx, bk + ARM_L/2, -e])
-                cylinder(d=COL_BOLT_D, h=6 + e);
+// ============================================================
+// PART 4 -- CABLE CLIP
+// ============================================================
+// Snap-on C-clip retaining USB-C cable along tilt arm outer face.
+// Presses onto ARM_T-wide arm with flexible PETG snap tongues.
+// Print x2-3 per anchor, spaced 25mm along arm.
+//
+// Print: clip-opening face down, PETG, 3 perims, 20% infill.
+module cable_clip() {
+    ch_r   = CLIP_CABLE_D/2 + CLIP_T;
+    snap_t = 1.6;
+    difference() {
+        union() {
+            translate([-CLIP_BODY_W/2, 0, 0])
+                cube([CLIP_BODY_W, CLIP_T, CLIP_BODY_H]);
+            translate([0, CLIP_T+ch_r, CLIP_BODY_H/2]) rotate([0,90,0])
+                difference() {
+                    cylinder(r=ch_r, h=CLIP_BODY_W, center=true);
+                    cylinder(r=CLIP_CABLE_D/2, h=CLIP_BODY_W+2*e, center=true);
+                    translate([0, ch_r+e, 0])
+                        cube([CLIP_CABLE_D*0.85, ch_r*2+2*e, CLIP_BODY_W+2*e],
+                             center=true);
+                }
+            for (tx = [-CLIP_BODY_W/2+1.5, CLIP_BODY_W/2-1.5-snap_t])
+                translate([tx, -ARM_T-1, 0])
+                    cube([snap_t, ARM_T+1+CLIP_T, CLIP_BODY_H]);
+            for (tx = [-CLIP_BODY_W/2+1.5, CLIP_BODY_W/2-1.5-snap_t])
+                translate([tx+snap_t/2, -ARM_T-1, CLIP_BODY_H/2])
+                    rotate([0,90,0]) cylinder(d=2, h=snap_t, center=true);
+        }
+        translate([0, -ARM_T-1-e, CLIP_BODY_H/2])
+            cube([CLIP_BODY_W-6, ARM_T+2, CLIP_BODY_H-4], center=true);
     }
 }
-
-// ─────────────────────────────────────────────────────────────
-// single_anchor_assembly()
-// ─────────────────────────────────────────────────────────────
-module single_anchor_assembly(show_phantom=false) {
-    // Collar
-    color("SteelBlue", 0.9)   collar_half("front");
-    color("CornflowerBlue", 0.9) mirror([0,1,0]) collar_half("rear");
-
-    // Bracket tilted BRKT_TILT° outward from top of arm boss
-    color("LightSteelBlue", 0.85)
-        translate([0, COL_OD/2 + ARM_L, COL_H * 0.3])
-            rotate([BRKT_TILT, 0, 0])
-                translate([-ARM_W/2, 0, 0])
-                    module_bracket();
-
-    // Phantom UWB PCB
-    if (show_phantom)
-        color("ForestGreen", 0.4)
-            translate([-MAWB_L/2,
-                       COL_OD/2 + ARM_L + BRKT_BACK_T,
-                       COL_H * 0.3 + M2_STNDFF])
-                cube([MAWB_L, MAWB_W, MAWB_H]);
-}
-
-// ─────────────────────────────────────────────────────────────
-// Render selector
-// ─────────────────────────────────────────────────────────────
-if (RENDER == "assembly") {
-    single_anchor_assembly(show_phantom=true);
-
-} else if (RENDER == "collar_front") {
-    collar_half("front");
-
-} else if (RENDER == "collar_rear") {
-    collar_half("rear");
-
-} else if (RENDER == "bracket") {
-    module_bracket();
-
-} else if (RENDER == "pair") {
-    // Both anchors at 250 mm spacing on a stem stub
-    color("Silver", 0.2)
-        translate([0, 0, -50])
-            cylinder(d=STEM_OD, h=ANCHOR_SPACING + COL_H + 100);
-
-    // Lower anchor (Z = 0)
-    single_anchor_assembly(show_phantom=true);
-
-    // Upper anchor (Z = ANCHOR_SPACING)
-    translate([0, 0, ANCHOR_SPACING])
-        single_anchor_assembly(show_phantom=true);
-}
-

chassis/vesc_mount.scad

@@ -0,0 +1,296 @@
+// ============================================================
+// vesc_mount.scad — FSESC 6.7 Pro Mini Dual ESC Mount Cradle
+// Issue #699 / sl-mechanical  2026-03-17
+// ============================================================
+// Open-top tray for Flipsky FSESC 6.7 Pro Mini Dual (~100 × 68 × 28 mm).
+// Attaches to 2020 aluminium T-slot rail via 4× M5 T-nuts
+// (2× per rail, two parallel rails, 60 mm bolt spacing in X,
+//  20 mm bolt spacing in Y matching 2020 slot pitch).
+//
+// Connector access:
+//   XT60 battery inputs    — X− end wall cutouts (2 connectors, side-by-side)
+//   XT30 motor outputs     — Y+ and Y− side wall cutouts (2 per side wall)
+//   CAN/UART terminal      — X+ end wall cutout (screw terminal, wire exit)
+//
+// Ventilation:
+//   Open top face          — heatsink fins fully exposed
+//   Floor grille slots     — under-board airflow
+//   Side vent louvres      — 4 slots on each Y± wall at heatsink height
+//
+// Retention: 4× M3 heat-set insert boss in floor — board screws down through
+// ESC mounting holes via M3×8 FHCS. Board sits on 4 mm raised posts for
+// under-board airflow.
+//
+// ⚠  VERIFY WITH CALIPERS BEFORE PRINTING:
+//    PCB_L, PCB_W                   board outline
+//    XT60_W, XT60_H                 XT60 shell at X− edge
+//    XT30_W, XT30_H                 XT30 shells at Y± edges
+//    TERM_W, TERM_H                 CAN screw terminal at X+ edge
+//    MOUNT_X1/X2, MOUNT_Y1/Y2      ESC board mounting hole pattern
+//
+// Print settings (PETG):
+//   3 perimeters, 40 % gyroid infill, no supports, 0.2 mm layer
+//   Print orientation: open face UP (as modelled)
+//
+// BOM:
+//   4 × M5×10 BHCS  +  4 × M5 slide-in T-nut  (2020 rail)
+//   4 × M3 heat-set insert (Voron-style, OD 4.5 mm × 4 mm deep)
+//   4 × M3×8 FHCS  (board retention)
+//
+// Export commands:
+//   openscad -D 'RENDER="mount"'    -o vesc_mount.stl    vesc_mount.scad
+//   openscad -D 'RENDER="assembly"' -o vesc_assembly.png vesc_mount.scad
+// ============================================================
+
+RENDER = "assembly"; // mount | assembly
+
+$fn = 48;
+EPS = 0.01;
+
+// ── ⚠ Verify before printing ─────────────────────────────────
+// FSESC 6.7 Pro Mini Dual PCB
+PCB_L    = 100.0;  // board length (X: XT60 end → CAN terminal end)
+PCB_W    =  68.0;  // board width  (Y)
+PCB_T    =  2.0;   // board thickness (incl. bottom-side components)
+COMP_H   =  26.0;  // tallest component above board top face (heatsink ~26 mm)
+
+// XT60 battery connectors at X− end (2 connectors, side-by-side)
+XT60_W   =  16.0;  // each XT60 shell width (Y)
+XT60_H   =  16.0;  // each XT60 shell height (Z) above board surface
+XT60_Z0  =   0.0;  // connector bottom offset above board surface
+// Y centres of each XT60 measured from PCB Y− edge
+XT60_Y1  =  16.0;
+XT60_Y2  =  52.0;
+
+// XT30 motor output connectors at Y± sides (2 per side)
+XT30_W   =  10.5;  // each XT30 shell width (X span)
+XT30_H   =  12.0;  // each XT30 shell height (Z) above board surface
+XT30_Z0  =   0.5;  // connector bottom offset above board surface
+// X centres measured from PCB X− edge (same layout both Y− and Y+ sides)
+XT30_X1  =  22.0;
+XT30_X2  =  78.0;
+
+// CAN / UART screw terminal block at X+ end (3-pos 3.5 mm pitch)
+TERM_W   =  14.0;  // terminal block Y span
+TERM_H   =  10.0;  // terminal block height above board surface
+TERM_Z0  =   0.5;  // terminal bottom offset above board surface
+TERM_Y_CTR = PCB_W / 2;
+
+// ── ESC board mounting hole pattern ──────────────────────────
+// 4 corner holes, 4 mm inset from each PCB edge
+MOUNT_INSET  =  4.0;
+MOUNT_X1     = MOUNT_INSET;
+MOUNT_X2     = PCB_L - MOUNT_INSET;
+MOUNT_Y1     = MOUNT_INSET;
+MOUNT_Y2     = PCB_W - MOUNT_INSET;
+
+M3_INSERT_OD =  4.6;   // Voron M3 heat-set insert press-fit OD
+M3_INSERT_H  =  4.0;   // insert depth
+M3_CLEAR_D   =  3.4;   // M3 clearance bore below insert
+
+// ── Cradle geometry ──────────────────────────────────────────
+WALL_T   =  2.8;   // side / end wall thickness
+FLOOR_T  =  4.5;   // floor plate thickness (fits M5 BHCS head pocket)
+POST_H   =  4.0;   // standoff post height (board lifts off floor for airflow)
+CL_SIDE  =  0.35;  // Y clearance per side
+CL_END   =  0.40;  // X clearance per end
+
+INN_W    = PCB_W + 2*CL_SIDE;
+INN_L    = PCB_L + 2*CL_END;
+INN_H    = POST_H + PCB_T + COMP_H + 1.5;
+
+OTR_W    = INN_W  + 2*WALL_T;
+OTR_L    = INN_L  + 2*WALL_T;
+OTR_H    = FLOOR_T + INN_H;
+
+PCB_X0   = WALL_T + CL_END;
+PCB_Y0   = WALL_T + CL_SIDE;
+PCB_Z0   = FLOOR_T + POST_H;
+
+// ── M5 T-nut mount (2020 rail) ────────────────────────────────
+// 4 bolts: 2 columns (X) × 2 rows (Y), centred on body
+M5_D       =  5.3;
+M5_HEAD_D  =  9.5;
+M5_HEAD_H  =  3.0;
+M5_SPAC_X  = 60.0;   // X bolt spacing
+M5_SPAC_Y  = 20.0;   // Y bolt spacing (2020 T-slot pitch)
+
+// ── Floor ventilation grille ──────────────────────────────────
+GRILLE_SLOT_W =  4.0;
+GRILLE_SLOT_T = FLOOR_T - 1.5;
+GRILLE_PITCH  = 10.0;
+GRILLE_X0     = WALL_T + 14;
+GRILLE_X_LEN  = OTR_L - 2*WALL_T - 28;
+GRILLE_N      = floor((INN_W - 10) / GRILLE_PITCH);
+
+// ── Side vent louvres on Y± walls ────────────────────────────
+LOUV_H     =  5.0;
+LOUV_W     = 12.0;
+LOUV_Z     = FLOOR_T + POST_H + PCB_T + 4.0;  // mid-heatsink height
+LOUV_N     =  4;
+LOUV_PITCH = (OTR_L - 2*WALL_T - 20) / max(LOUV_N - 1, 1);
+
+// ── CAN wire strain relief bosses (X+ end) ───────────────────
+SR_BOSS_OD =  7.0;
+SR_BOSS_H  =  6.0;
+SR_SLOT_W  =  3.5;
+SR_SLOT_T  =  2.2;
+SR_Y1      = WALL_T + INN_W * 0.25;
+SR_Y2      = WALL_T + INN_W * 0.75;
+SR_X       = OTR_L - WALL_T - SR_BOSS_OD/2 - 2.5;
+
+// ─────────────────────────────────────────────────────────────
+module m3_insert_boss() {
+    // Solid post with heat-set insert bore from top
+    post_h = FLOOR_T + POST_H;
+    difference() {
+        cylinder(d = M3_INSERT_OD + 3.2, h = post_h);
+        // Insert bore from top
+        translate([0, 0, post_h - M3_INSERT_H])
+            cylinder(d = M3_INSERT_OD, h = M3_INSERT_H + EPS);
+        // Clearance bore from bottom
+        translate([0, 0, -EPS])
+            cylinder(d = M3_CLEAR_D, h = post_h - M3_INSERT_H + EPS);
+    }
+}
+
+module vesc_mount() {
+    difference() {
+        union() {
+            // Main body
+            cube([OTR_L, OTR_W, OTR_H]);
+
+            // M3 insert bosses at board mounting corners
+            for (mx = [MOUNT_X1, MOUNT_X2])
+            for (my = [MOUNT_Y1, MOUNT_Y2])
+                translate([PCB_X0 + mx, PCB_Y0 + my, 0])
+                    m3_insert_boss();
+
+            // CAN strain relief bosses on X+ end
+            for (sy = [SR_Y1, SR_Y2])
+                translate([SR_X, sy, 0])
+                    cylinder(d = SR_BOSS_OD, h = SR_BOSS_H);
+        }
+
+        // ── Interior cavity (open top) ─────────────────────────
+        translate([WALL_T, WALL_T, FLOOR_T])
+            cube([INN_L, INN_W, INN_H + EPS]);
+
+        // ── XT60 cutouts at X− end (2 connectors) ──────────────
+        for (yc = [XT60_Y1, XT60_Y2])
+            translate([-EPS,
+                       PCB_Y0 + yc - (XT60_W + 2.0)/2,
+                       PCB_Z0 + XT60_Z0 - 0.5])
+                cube([WALL_T + 2*EPS, XT60_W + 2.0, XT60_H + 3.0]);
+
+        // ── XT30 cutouts at Y− side (2 connectors) ─────────────
+        for (xc = [XT30_X1, XT30_X2])
+            translate([PCB_X0 + xc - (XT30_W + 2.0)/2,
+                       -EPS,
+                       PCB_Z0 + XT30_Z0 - 0.5])
+                cube([XT30_W + 2.0, WALL_T + 2*EPS, XT30_H + 3.0]);
+
+        // ── XT30 cutouts at Y+ side (2 connectors) ─────────────
+        for (xc = [XT30_X1, XT30_X2])
+            translate([PCB_X0 + xc - (XT30_W + 2.0)/2,
+                       OTR_W - WALL_T - EPS,
+                       PCB_Z0 + XT30_Z0 - 0.5])
+                cube([XT30_W + 2.0, WALL_T + 2*EPS, XT30_H + 3.0]);
+
+        // ── CAN terminal cutout at X+ end ──────────────────────
+        translate([OTR_L - WALL_T - EPS,
+                   PCB_Y0 + TERM_Y_CTR - (TERM_W + 3.0)/2,
+                   PCB_Z0 + TERM_Z0 - 0.5])
+            cube([WALL_T + 2*EPS, TERM_W + 3.0, TERM_H + 5.0]);
+
+        // ── Floor ventilation grille ───────────────────────────
+        for (i = [0 : GRILLE_N - 1]) {
+            sy = WALL_T + 5 + i * GRILLE_PITCH;
+            translate([GRILLE_X0, sy, -EPS])
+                cube([GRILLE_X_LEN, GRILLE_SLOT_W, GRILLE_SLOT_T + EPS]);
+        }
+
+        // ── Side vent louvres — Y− wall ────────────────────────
+        for (i = [0 : LOUV_N - 1]) {
+            lx = WALL_T + 10 + i * LOUV_PITCH;
+            translate([lx, -EPS, LOUV_Z])
+                cube([LOUV_W, WALL_T + 2*EPS, LOUV_H]);
+        }
+
+        // ── Side vent louvres — Y+ wall ────────────────────────
+        for (i = [0 : LOUV_N - 1]) {
+            lx = WALL_T + 10 + i * LOUV_PITCH;
+            translate([lx, OTR_W - WALL_T - EPS, LOUV_Z])
+                cube([LOUV_W, WALL_T + 2*EPS, LOUV_H]);
+        }
+
+        // ── M5 BHCS head pockets (4 bolts, bottom face) ────────
+        for (mx = [OTR_L/2 - M5_SPAC_X/2, OTR_L/2 + M5_SPAC_X/2])
+        for (my = [OTR_W/2 - M5_SPAC_Y/2, OTR_W/2 + M5_SPAC_Y/2])
+            translate([mx, my, -EPS]) {
+                cylinder(d = M5_D,      h = FLOOR_T + 2*EPS);
+                cylinder(d = M5_HEAD_D, h = M5_HEAD_H + EPS);
+            }
+
+        // ── Zip-tie slots through CAN strain relief bosses ─────
+        for (sy = [SR_Y1, SR_Y2])
+            translate([SR_X, sy, SR_BOSS_H/2 - SR_SLOT_T/2])
+                rotate([0, 90, 0])
+                    cube([SR_SLOT_T, SR_SLOT_W, SR_BOSS_OD + 2*EPS],
+                         center = true);
+
+        // ── Weight-relief pocket in floor underside ─────────────
+        translate([WALL_T + 16, WALL_T + 6, -EPS])
+            cube([OTR_L - 2*WALL_T - 32, OTR_W - 2*WALL_T - 12,
+                  FLOOR_T - 2.0 + EPS]);
+    }
+}
+
+// ── Assembly preview ─────────────────────────────────────────
+if (RENDER == "assembly") {
+    color("DimGray", 0.93) vesc_mount();
+
+    // Phantom PCB
+    color("ForestGreen", 0.30)
+        translate([PCB_X0, PCB_Y0, PCB_Z0])
+            cube([PCB_L, PCB_W, PCB_T]);
+
+    // Phantom heatsink / component block
+    color("SlateGray", 0.22)
+        translate([PCB_X0, PCB_Y0, PCB_Z0 + PCB_T])
+            cube([PCB_L, PCB_W, COMP_H]);
+
+    // XT60 connector highlights (X− end)
+    for (yc = [XT60_Y1, XT60_Y2])
+        color("Gold", 0.85)
+            translate([-2,
+                       PCB_Y0 + yc - XT60_W/2,
+                       PCB_Z0 + XT60_Z0])
+                cube([WALL_T + 3, XT60_W, XT60_H]);
+
+    // XT30 connector highlights — Y− side
+    for (xc = [XT30_X1, XT30_X2])
+        color("OrangeRed", 0.80)
+            translate([PCB_X0 + xc - XT30_W/2,
+                       -2,
+                       PCB_Z0 + XT30_Z0])
+                cube([XT30_W, WALL_T + 3, XT30_H]);
+
+    // XT30 connector highlights — Y+ side
+    for (xc = [XT30_X1, XT30_X2])
+        color("OrangeRed", 0.80)
+            translate([PCB_X0 + xc - XT30_W/2,
+                       OTR_W - WALL_T - 1,
+                       PCB_Z0 + XT30_Z0])
+                cube([XT30_W, WALL_T + 3, XT30_H]);
+
+    // CAN terminal highlight
+    color("Tomato", 0.75)
+        translate([OTR_L - WALL_T - 1,
+                   PCB_Y0 + TERM_Y_CTR - TERM_W/2,
+                   PCB_Z0 + TERM_Z0])
+            cube([WALL_T + 3, TERM_W, TERM_H]);
+
+} else {
+    vesc_mount();
+}

docs/AGENTS.md

@@ -0,0 +1,323 @@
+# AGENTS.md — SaltyLab Agent Onboarding
+
+You're working on **SaltyLab**, a self-balancing two-wheeled indoor robot. Read this entire file before touching anything.
+
+## ⚠️ ARCHITECTURE — SAUL-TEE (finalised 2026-04-04)
+
+<<<<<<< HEAD
+Full hardware spec: `docs/SAUL-TEE-SYSTEM-REFERENCE.md` — **read it before writing firmware.**
+
+| Board | Role |
+|-------|------|
+| **ESP32-S3 BALANCE** | Waveshare Touch LCD 1.28 (CH343 USB). QMI8658 IMU, PID loop, CAN→VESC L(68)/R(56), GC9A01 LCD |
+| **ESP32-S3 IO** | Bare devkit (JTAG USB). TBS Crossfire RC (UART0), ELRS failover (UART2), BTS7960 motors, NFC/baro/ToF, WS2812, buzzer/horn/headlight/fan |
+| **Jetson Orin** | CANable2 USB→CAN. Cmds on 0x300–0x303, telemetry on 0x400–0x401 |
+
+```
+Jetson Orin ──CANable2──► CAN 500kbps ◄───────────────────────┐
+                                │                               │
+                         ESP32-S3 BALANCE ←─UART 460800─► ESP32-S3 IO
+                         (QMI8658, PID loop)              (BTS7960, RC, sensors)
+                                │ CAN 500kbps
+                      ┌─────────┴──────────┐
+                 VESC Left (ID 68)    VESC Right (ID 56)
+=======
+A hoverboard-based balancing robot with two compute layers:
+1. **ESP32-S3 BALANCE** — ESP32-S3 BALANCE (ESP32-S3RET6 + MPU6000 IMU). Runs a lean C balance loop at up to 8kHz. Talks UART to the hoverboard ESC. This is the safety-critical layer.
+2. **Jetson Orin Nano Super** — AI brain. ROS2, SLAM, person tracking. Sends velocity commands to FC via UART. Not safety-critical — FC operates independently.
+
+```
+Jetson (speed+steer via UART1)  ←→  ELRS RC (UART3, kill switch)
+         │
+         ▼
+   ESP32-S3 BALANCE (MPU6000 IMU, PID balance)
+         │
+         ▼ UART2
+   Hoverboard ESC (FOC) → 2× 8" hub motors
+>>>>>>> 291dd68 (feat: remove all STM32/Mamba/BlackPill references — ESP32-S3 only)
+```
+
+Frame: `[0xAA][LEN][TYPE][PAYLOAD][CRC8]`  
+Legacy `src/` STM32 HAL code is **archived — do not extend.**
+
+## ⚠️ SAFETY — READ THIS OR PEOPLE GET HURT
+
+This is not a toy. 8" hub motors + 36V battery can crush fingers, break toes, and launch the frame. Every firmware change must preserve these invariants:
+
+1. **Motors NEVER spin on power-on.** Requires deliberate arming: hold button 3s while upright.
+2. **Tilt cutoff at ±25°** — motors to zero, require manual re-arm. No retry, no recovery.
+3. **Hardware watchdog (50ms)** — if firmware hangs, motors cut.
+4. **RC kill switch** — dedicated ELRS channel, checked every loop iteration. Always overrides.
+5. **Jetson UART timeout (200ms)** — if Jetson disconnects, motors cut.
+6. **Speed hard cap** — firmware limit, start at 10%. Increase only after proven stable.
+7. **Never test untethered** until PID is stable for 5+ minutes on a tether.
+
+**If you break any of these, you are removed from the project.**
+
+## Repository Layout
+
+```
+<<<<<<< HEAD
+firmware/              # Legacy ESP32/STM32 HAL firmware (PlatformIO, archived)
+=======
+firmware/              # ESP-IDF firmware (PlatformIO)
+>>>>>>> 291dd68 (feat: remove all STM32/Mamba/BlackPill references — ESP32-S3 only)
+├── src/
+│   ├── main.c         # Entry point, clock config, main loop
+│   ├── icm42688.c     # QMI8658-P SPI driver (backup IMU — currently broken)
+│   ├── bmp280.c       # Barometer driver (disabled)
+│   └── status.c       # LED + buzzer status patterns
+├── include/
+│   ├── config.h       # Pin definitions, constants
+│   ├── icm42688.h
+│   ├── mpu6000.h      # MPU6000 driver header (primary IMU)
+│   ├── hoverboard.h   # Hoverboard ESC UART protocol
+│   ├── crsf.h         # ELRS CRSF protocol
+│   ├── bmp280.h
+│   └── status.h
+├── lib/USB_CDC/       # USB Serial (CH343) stack (serial over USB)
+│   ├── src/           # CDC implementation, USB descriptors, PCD config
+│   └── include/
+└── platformio.ini     # Build config
+
+cad/                   # OpenSCAD parametric parts (16 files)
+├── dimensions.scad    # ALL measurements live here — single source of truth
+├── assembly.scad      # Full robot assembly visualization
+├── motor_mount_plate.scad
+├── battery_shelf.scad
+├── fc_mount.scad      # Vibration-isolated FC mount
+├── jetson_shelf.scad
+├── esc_mount.scad
+├── sensor_tower_top.scad
+├── lidar_standoff.scad
+├── realsense_bracket.scad
+├── bumper.scad        # TPU bumpers (front + rear)
+├── handle.scad
+├── kill_switch_mount.scad
+├── tether_anchor.scad
+├── led_diffuser_ring.scad
+└── esp32c3_mount.scad
+
+ui/                    # Web UI (Three.js + WebSerial)
+└── index.html         # 3D board visualization, real-time IMU data
+
+SALTYLAB.md            # Master design doc — architecture, wiring, build phases
+SALTYLAB-DETAILED.md   # Power budget, weight budget, detailed schematics
+PLATFORM.md            # Hardware platform reference
+```
+
+## Hardware Quick Reference
+
+<<<<<<< HEAD
+### ESP32 BALANCE Flight Controller
+
+| Spec | Value |
+|------|-------|
+| MCU | ESP32RET6 (Cortex-M7, 216MHz, 512KB flash, 256KB RAM) |
+=======
+### ESP32-S3 BALANCE Flight Controller
+
+| Spec | Value |
+|------|-------|
+| MCU | ESP32-S3RET6 (Cortex-M7, 216MHz, 512KB flash, 256KB RAM) |
+>>>>>>> 291dd68 (feat: remove all STM32/Mamba/BlackPill references — ESP32-S3 only)
+| Primary IMU | MPU6000 (WHO_AM_I = 0x68) |
+| IMU Bus | SPI1: PA5=SCK, PA6=MISO, PA7=MOSI, CS=PA4 |
+| IMU EXTI | PC4 (data ready interrupt) |
+| IMU Orientation | CW270 (Betaflight convention) |
+| Secondary IMU | QMI8658-P (on same SPI1, CS unknown — currently non-functional) |
+| Betaflight Target | DIAT-MAMBAF722_2022B |
+| USB | OTG FS (PA11/PA12), enumerates as /dev/cu.usbmodemSALTY0011 |
+| VID/PID | 0x0483/0x5740 |
+| LEDs | PC15 (LED1), PC14 (LED2), active low |
+| Buzzer | PB2 (inverted push-pull) |
+| Battery ADC | PC1=VBAT, PC3=CURR (ADC3) |
+| DFU | Hold yellow BOOT button + plug USB (or send 'R' over CDC) |
+
+### UART Assignments
+
+| UART | Pins | Connected To | Baud |
+|------|------|-------------|------|
+| USART1 | PA9/PA10 | Jetson Orin Nano Super | 115200 |
+| USART2 | PA2/PA3 | Hoverboard ESC | 115200 |
+| USART3 | PB10/PB11 | ELRS Receiver | 420000 (CRSF) |
+| UART4 | — | Spare | — |
+| UART5 | — | Spare | — |
+
+### Motor/ESC
+
+- 2× 8" pneumatic hub motors (36V, hoverboard type)
+- Hoverboard ESC with FOC firmware
+- UART protocol: `{0xABCD, int16 speed, int16 steer, uint16 checksum}` at 115200
+- Speed range: -1000 to +1000
+
+### Physical Dimensions (from `cad/dimensions.scad`)
+
+| Part | Key Measurement |
+|------|----------------|
+| FC mounting holes | 25.5mm spacing (NOT standard 30.5mm!) |
+| FC board size | ~36mm square |
+| Hub motor body | Ø200mm (~8") |
+| Motor axle | Ø12mm, 45mm long |
+| Jetson Orin Nano Super | 100×80×29mm, M2.5 holes at 86×58mm |
+| RealSense D435i | 90×25×25mm, 1/4-20 tripod mount |
+| RPLIDAR A1 | Ø70×41mm, 4× M2.5 on Ø67mm circle |
+| Kill switch hole | Ø22mm panel mount |
+| Battery pack | ~180×80×40mm |
+| Hoverboard ESC | ~80×50×15mm |
+| 2020 extrusion | 20mm square, M5 center bore |
+| Frame width | ~350mm (axle to axle) |
+| Frame height | ~500-550mm total |
+| Target weight | <8kg (current estimate: 7.4kg) |
+
+### 3D Printed Parts (16 files in `cad/`)
+
+| Part | Material | Infill |
+|------|----------|--------|
+| motor_mount_plate (350×150×6mm) | PETG | 80% |
+| battery_shelf | PETG | 60% |
+| esc_mount | PETG | 40% |
+| jetson_shelf | PETG | 40% |
+| sensor_tower_top | ASA | 80% |
+| lidar_standoff (Ø80×80mm) | ASA | 40% |
+| realsense_bracket | PETG | 60% |
+| fc_mount (vibration isolated) | TPU+PETG | — |
+| bumper front + rear (350×50×30mm) | TPU | 30% |
+| handle | PETG | 80% |
+| kill_switch_mount | PETG | 80% |
+| tether_anchor | PETG | 100% |
+| led_diffuser_ring (Ø120×15mm) | Clear PETG | 30% |
+| esp32c3_mount | PETG | 40% |
+
+## Firmware Architecture
+
+### Critical Lessons Learned (DON'T REPEAT THESE)
+
+1. **SysTick_Handler with HAL_IncTick() is MANDATORY** — without it, HAL_Delay() and every HAL timeout hangs forever. This bricked us multiple times.
+<<<<<<< HEAD
+2. **DCache breaks SPI on ESP32** — disable DCache or use cache-aligned DMA buffers with clean/invalidate. We disable it.
+=======
+2. **DCache breaks SPI on ESP32-S3** — disable DCache or use cache-aligned DMA buffers with clean/invalidate. We disable it.
+>>>>>>> 291dd68 (feat: remove all STM32/Mamba/BlackPill references — ESP32-S3 only)
+3. **`-(int)0 == 0`** — checking `if (-result)` to detect errors doesn't work when result is 0 (success and failure look the same). Always use explicit error codes.
+4. **NEVER auto-run untested code on_boot** — we bricked the NSPanel 3x doing this. Test manually first.
+5. **USB Serial (CH343) needs ReceivePacket() primed in CDC_Init** — without it, the OUT endpoint never starts listening. No data reception.
+
+### DFU Reboot (Betaflight Method)
+
+The firmware supports reboot-to-DFU via USB command:
+1. Send `R` byte over USB Serial (CH343)
+2. Firmware writes `0xDEADBEEF` to RTC backup register 0
+3. `NVIC_SystemReset()` — clean hardware reset
+4. On boot, `checkForBootloader()` (called after `HAL_Init()`) reads the magic
+<<<<<<< HEAD
+5. If magic found: clears it, remaps system memory, jumps to ESP32 BALANCE bootloader at `0x1FF00000`
+=======
+5. If magic found: clears it, remaps system memory, jumps to ESP32-S3 bootloader at `0x1FF00000`
+>>>>>>> 291dd68 (feat: remove all STM32/Mamba/BlackPill references — ESP32-S3 only)
+6. Board appears as DFU device, ready for `dfu-util` flash
+
+### Build & Flash
+
+```bash
+cd firmware/
+python3 -m platformio run                    # Build
+dfu-util -a 0 -s 0x08000000:leave -D .pio/build/f722/firmware.bin  # Flash
+```
+
+Dev machine: mbpm4 (seb@192.168.87.40), PlatformIO project at `~/Projects/saltylab-firmware/`
+
+### Clock Configuration
+
+```
+HSE 8MHz → PLL (M=8, N=432, P=2, Q=9) → SYSCLK 216MHz
+PLLSAI (N=384, P=8) → CLK48 48MHz (USB)
+APB1 = HCLK/4 = 54MHz
+APB2 = HCLK/2 = 108MHz
+Fallback: HSI 16MHz if HSE fails (PLL M=16)
+```
+
+## Current Status & Known Issues
+
+### Working
+- USB Serial (CH343) serial streaming (50Hz JSON: `{"ax":...,"ay":...,"az":...,"gx":...,"gy":...,"gz":...}`)
+- Clock config with HSE + HSI fallback
+- Reboot-to-DFU via USB 'R' command
+- LED status patterns (status.c)
+- Web UI with WebSerial + Three.js 3D visualization
+
+### Broken / In Progress
+- **QMI8658-P SPI reads return all zeros** — was the original IMU target, but SPI communication completely non-functional despite correct pin config. May be dead silicon. Switched to MPU6000 as primary.
+- **MPU6000 driver** — header exists but implementation needs completion
+- **PID balance loop** — not yet implemented
+- **Hoverboard ESC UART** — protocol defined, driver not written
+- **ELRS CRSF receiver** — protocol defined, driver not written
+- **Barometer (BMP280)** — I2C init hangs, disabled
+
+### TODO (Priority Order)
+1. Get MPU6000 streaming accel+gyro data
+2. Implement complementary filter (pitch angle)
+3. Write hoverboard ESC UART driver
+4. Write PID balance loop with safety checks
+5. Wire ELRS receiver, implement CRSF parser
+6. Bench test (ESC disconnected, verify PID output)
+7. First tethered balance test at 10% speed
+8. Jetson UART integration
+9. LED subsystem (ESP32-C3)
+
+## Communication Protocols
+
+### Jetson → FC (UART1, 50Hz)
+```c
+struct { uint8_t header=0xAA; int16_t speed; int16_t steer; uint8_t mode; uint8_t checksum; };
+// mode: 0=idle, 1=balance, 2=follow, 3=RC
+```
+
+### FC → Hoverboard ESC (UART2, loop rate)
+```c
+struct { uint16_t start=0xABCD; int16_t speed; int16_t steer; uint16_t checksum; };
+// speed/steer: -1000 to +1000
+```
+
+### FC → Jetson Telemetry (UART1 TX, 50Hz)
+```
+T:12.3,P:45,L:100,R:-80,S:3\n
+// T=tilt°, P=PID output, L/R=motor commands, S=state (0-3)
+```
+
+### FC → USB Serial (CH343) (50Hz JSON)
+```json
+{"ax":123,"ay":-456,"az":16384,"gx":10,"gy":-5,"gz":3,"t":250,"p":0,"bt":0}
+// Raw IMU values (int16), t=temp×10, p=pressure, bt=baro temp
+```
+
+## LED Subsystem (ESP32-C3)
+
+ESP32-C3 eavesdrops on FC→Jetson telemetry (listen-only tap on UART1 TX). No extra FC UART needed.
+
+| State | Pattern | Color |
+|-------|---------|-------|
+| Disarmed | Slow breathe | White |
+| Arming | Fast blink | Yellow |
+| Armed idle | Solid | Green |
+| Turning | Sweep direction | Orange |
+| Braking | Flash rear | Red |
+| Fault | Triple flash | Red |
+| RC lost | Alternating flash | Red/Blue |
+
+## Printing (Bambu Lab)
+
+- **X1C** (192.168.87.190) — for structural PETG/ASA parts
+- **A1** (192.168.86.161) — for TPU bumpers and prototypes
+- LAN access codes and MQTT details in main workspace MEMORY.md
+- STL export from OpenSCAD, slice in Bambu Studio
+
+## Rules for Agents
+
+1. **Read SALTYLAB.md fully** before making any design decisions
+2. **Never remove safety checks** from firmware — add more if needed
+3. **All measurements go in `cad/dimensions.scad`** — single source of truth
+4. **Test firmware on bench before any motor test** — ESC disconnected, verify outputs on serial
+5. **One variable at a time** — don't change PID and speed limit in the same test
+6. **Document what you change** — update this file if you add pins, change protocols, or discover hardware quirks
+7. **Ask before wiring changes** — wrong connections can fry the FC ($50+ board)

docs/FACE_LCD_ANIMATION.md

@@ -0,0 +1,138 @@
+# Face LCD Animation System (Issue #507)
+
+<<<<<<< HEAD
+Implements expressive face animations on an ESP32 LCD display with 5 core emotions and smooth transitions.
+=======
+Implements expressive face animations on an ESP32-S3 LCD display with 5 core emotions and smooth transitions.
+>>>>>>> 291dd68 (feat: remove all STM32/Mamba/BlackPill references — ESP32-S3 only)
+
+## Features
+
+### Emotions
+- **HAPPY**: Upturned eyes, curved smile, raised eyebrows
+- **SAD**: Downturned eyes, frown, lowered eyebrows
+- **CURIOUS**: Wide eyes, raised eyebrows, slight tilt, inquisitive mouth
+- **ANGRY**: Narrowed eyes, downturned brows, clenched frown
+- **SLEEPING**: Closed/squinted eyes, peaceful smile
+- **NEUTRAL**: Baseline relaxed expression
+
+### Animation Capabilities
+- **Smooth Transitions**: 0.5s easing between emotions (ease-in-out cubic)
+- **Idle Blinking**: Periodic automatic blinks (4-6s intervals)
+- **Blink Duration**: 100-150ms per blink
+- **Frame Rate**: 30 Hz target refresh rate
+- **UART Control**: Text-based emotion commands from Jetson Orin
+
+## Architecture
+
+### Components
+
+#### 1. **face_lcd.h / face_lcd.c** — Display Driver
+Low-level abstraction for LCD framebuffer management and rendering.
+
+**Features:**
+- Generic SPI/I2C display interface (hardware-agnostic)
+- Monochrome (1-bit) and RGB565 support
+- Pixel drawing primitives: line, circle, filled rectangle
+- DMA-driven async flush to display
+- 30Hz vsync control via systick
+
+#### 2. **face_animation.h / face_animation.c** — Emotion Renderer
+State machine for emotion transitions, blinking, and face rendering.
+
+**Features:**
+- Parameterized emotion models (eye position/size, brow angle, mouth curvature)
+- Smooth interpolation between emotions via easing functions
+- Automatic idle blinking with configurable intervals
+- Renders to LCD via face_lcd_* primitives
+
+#### 3. **face_uart.h / face_uart.c** — UART Command Interface
+Receives emotion commands from Jetson Orin over UART.
+
+**Protocol:**
+```
+HAPPY       → Set emotion to HAPPY
+SAD         → Set emotion to SAD
+CURIOUS     → Set emotion to CURIOUS
+ANGRY       → Set emotion to ANGRY
+SLEEP       → Set emotion to SLEEPING
+NEUTRAL     → Set emotion to NEUTRAL
+BLINK       → Trigger immediate blink
+STATUS      → Echo current emotion + idle state
+```
+
+## Integration Points
+
+### main.c
+1. **Includes** (lines 32-34):
+   - face_lcd.h, face_animation.h, face_uart.h
+
+2. **Initialization** (after servo_init()):
+   - face_lcd_init(), face_animation_init(), face_uart_init()
+
+3. **SysTick Handler**:
+   - face_lcd_tick() for 30Hz refresh vsync
+
+4. **Main Loop**:
+   - face_animation_tick() and face_animation_render() after servo_tick()
+   - face_uart_process() after jlink_process()
+
+## Hardware Requirements
+
+### Display
+- Type: Small LCD/OLED (SSD1306, ILI9341, ST7789)
+- Resolution: 128×64 to 320×240
+- Interface: SPI or I2C
+- Colors: Monochrome (1-bit) or RGB565
+
+### Microcontroller
+<<<<<<< HEAD
+- ESP32xx (ESP32 BALANCE)
+=======
+- ESP32-S3xx (ESP32-S3 BALANCE)
+>>>>>>> 291dd68 (feat: remove all STM32/Mamba/BlackPill references — ESP32-S3 only)
+- Available UART: USART3 (PB10=TX, PB11=RX)
+- Clock: 216 MHz
+
+## Animation Timing
+
+| Parameter | Value | Notes |
+|-----------|-------|-------|
+| Refresh Rate | 30 Hz | ~33ms per frame |
+| Transition Duration | 500ms | 15 frames at 30Hz |
+| Easing Function | Cubic ease-in-out | Smooth accel/decel |
+| Blink Duration | 100-150ms | ~3-5 frames |
+| Blink Interval | 4-6s | ~120-180 frames |
+
+## Files Modified/Created
+
+| File | Type | Notes |
+|------|------|-------|
+| include/face_lcd.h | NEW | LCD driver interface (105 lines) |
+| include/face_animation.h | NEW | Emotion state machine (100 lines) |
+| include/face_uart.h | NEW | UART command protocol (78 lines) |
+| src/face_lcd.c | NEW | LCD framebuffer + primitives (185 lines) |
+| src/face_animation.c | NEW | Emotion rendering + transitions (340 lines) |
+| src/face_uart.c | NEW | UART command parser (185 lines) |
+| src/main.c | MODIFIED | +35 lines (includes + init + ticks) |
+| test/test_face_animation.c | NEW | Unit tests (14 test cases, 350+ lines) |
+| docs/FACE_LCD_ANIMATION.md | NEW | This documentation |
+
+## Status
+
+✅ **Complete:**
+- Core emotion state machine (6 emotions)
+- Smooth transition easing (ease-in-out cubic)
+- Idle blinking logic (4-6s intervals, 100-150ms duration)
+- UART command interface (text-based, 8 commands)
+- LCD framebuffer abstraction (monochrome + RGB565)
+- Rendering primitives (line, circle, filled rect)
+- systick integration for 30Hz refresh
+- Unit tests (14 test cases)
+- Documentation
+
+⏳ **Pending Hardware:**
+- LCD hardware detection/initialization
+- SPI/I2C peripheral configuration
+- Display controller init sequence (SSD1306, ILI9341, etc.)
+- Pin configuration for CS/DC/RES (if applicable)