02217443ea
Consolidating seb/saltylab into saltylab-firmware before deleting the seed repo. - 16 OpenSCAD CAD models → cad/ - Design docs (SALTYLAB.md, PLATFORM.md, AGENTS.md, board-viz.html) → docs/
455 lines
18 KiB
Markdown
455 lines
18 KiB
Markdown
# SaltyLab — Detailed Build Plan 🔬⚖️
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Self-balancing two-wheeled indoor robot with AI brain.
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---
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## 1. Battery Analysis
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### Pack Specs (Begode Master V1 packs)
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- **Configuration per pack:** 10S (35V nominal, 42V full, 30V cutoff)
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- **Chemistry:** Li-ion 18650 or 21700
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- **Estimated capacity per pack:** ~450-500Wh (based on Master V1 total ~1800Wh ÷ 4 packs)
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- If 10S4P with 21700 5000mAh cells: 36V × 20Ah = **720Wh**
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- If 10S3P with 21700 5000mAh cells: 36V × 15Ah = **540Wh**
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- If 10S4P with 18650 3500mAh cells: 36V × 14Ah = **504Wh**
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- **Need to verify:** check cell count visible on pack, or weigh it
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### SaltyLab Battery Config: Single Pack
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- **Voltage:** 35V nominal (fits hoverboard ESC: designed for 36V/10S)
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- **Capacity:** ~500Wh (conservative estimate)
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- **Weight:** ~2-3kg per pack
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### Why Single Pack is Enough
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- SaltyLab is indoor-only, short missions
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- One pack gives 2-4 hours runtime (see estimates below)
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- Keep other 3 packs for SaltyRider and SaltyTank
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---
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## 2. Power Budget & Range Estimation
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### Component Power Draw
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| Component | Voltage | Current | Power (W) | Notes |
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|-----------|---------|---------|-----------|-------|
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| Jetson Nano | 5V | 2-4A | 10-20W | AI inference mode: ~15W avg |
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| RealSense D435i | 5V (USB) | 0.7A | 3.5W | Depth + RGB streaming |
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| RPLIDAR A1M8 | 5V | 0.5A | 2.5W | Spinning at 5.5Hz |
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| BNO055 IMU | 3.3V | 0.01A | 0.04W | Negligible |
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| ESC (idle/balance) | 36V | 0.3A | 10W | Maintaining balance, no movement |
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| LEDs + misc | 12V | 0.5A | 6W | Status LEDs, speaker |
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| DC-DC losses | — | — | ~5W | ~85% efficiency on converters |
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| **Subtotal (idle/balancing)** | | | **~47W** | |
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### Motor Power (Moving)
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| Activity | Per Motor | Total (2 motors) | Notes |
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|----------|-----------|-------------------|-------|
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| Balancing in place | 5-15W | 10-30W | Continuous micro-corrections |
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| Slow indoor movement (2 km/h) | 15-25W | 30-50W | Walking pace |
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| Normal indoor (5 km/h) | 30-50W | 60-100W | Brisk walk |
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| Fast / acceleration | 80-150W | 160-300W | Bursts, turning |
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| Climbing threshold/ramp | 100-200W | 200-400W | Short duration |
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### Total Power by Use Case
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| Mode | Electronics | Motors | Total | Notes |
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|------|-------------|--------|-------|-------|
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| **Idle (balancing)** | 47W | 20W | **~67W** | Standing still |
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| **Slow patrol** | 47W | 40W | **~87W** | Gentle movement |
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| **Normal follow** | 47W | 80W | **~127W** | Following person around house |
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| **Active (turning, accel)** | 47W | 200W | **~247W** | Bursts |
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### Range Estimates (Single 500Wh Pack)
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| Mode | Avg Power | Runtime | Distance |
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|------|-----------|---------|----------|
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| Idle (balancing) | 67W | **7.5 hours** | 0 km (stationary) |
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| Slow patrol (2 km/h) | 87W | **5.7 hours** | ~11 km |
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| Normal follow (5 km/h) | 127W | **3.9 hours** | ~20 km |
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| Mixed indoor use | ~100W avg | **5 hours** | ~15 km |
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| Aggressive (lots of turning) | 180W avg | **2.8 hours** | ~8 km |
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**Bottom line: 3-5 hours of indoor use on a single pack.** More than enough.
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### Weight Budget
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| Component | Weight (g) | Notes |
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|-----------|-----------|-------|
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| Battery pack (1x) | 2500 | Estimated, weigh to verify |
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| 2x 8" hub motors | 2400 | ~1200g each with tire |
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| ESC board | 150 | Single board |
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| Jetson Nano + heatsink | 280 | With Noctua fan |
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| RealSense D435i | 72 | Very light |
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| RPLIDAR A1M8 | 170 | With motor |
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| BNO055 breakout | 5 | Tiny |
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| DC-DC converters (2x) | 300 | 150g each |
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| Frame + brackets | 1200 | Aluminum + 3D printed |
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| Wiring + connectors | 200 | |
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| Bumpers (TPU) | 150 | |
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| **TOTAL** | **~7.4 kg** | Target: under 8 kg |
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---
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## 3. Detailed 2D Schematics
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### 3.1 Base Plate — Top View
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```
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350mm
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←─────────────────────────────────────→
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┌─────────────────────────────────────┐ ─┬─
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│ ○ ○ │ │
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│ ┌───────────────────────────┐ │ │
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│ │ MOTOR MOUNT PLATE │ │ │
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│ │ │ │ │
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│ │ ┌─────┐ ┌─────┐ │ │ │
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│ │ │AXLE │ │AXLE │ │ │ │ 200mm
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│ │ │ L │ │ R │ │ │ │
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│ │ └─────┘ └─────┘ │ │ │
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│ │ ↑ 250mm ↑ │ │ │
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│ │ └─────────────┘ │ │ │
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│ │ track width │ │ │
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│ └───────────────────────────┘ │ │
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│ ○ ○ │ │
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└─────────────────────────────────────┘ ─┴─
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○ = M5 mounting holes for vertical spine (4 corners)
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Axle holes: Ø14mm (standard hoverboard axle)
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Plate thickness: 6mm PETG
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Motor mount detail:
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┌──────────────┐
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│ ┌────────┐ │
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│ │ Ø14mm │ │ Two-piece clamp:
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│ │ axle │ │ Bottom: part of base plate
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│ │ hole │ │ Top: clamp plate with 2x M6 bolts
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│ └────────┘ │
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│ ○ ○ │ ○ = M6 clamp bolt holes
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└──────────────┘
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80mm
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```
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### 3.2 Side View — Full Assembly
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```
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FRONT →
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550mm ┬ ┌─────────┐
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│ │ RPLIDAR │ Ø80mm, 360° clear
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│ │ A1M8 │
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500mm │ ├─────────┤
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│ │ │ ← LIDAR standoff tube (80mm tall)
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│ │ │
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420mm │ ├─────────┤
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│ │RealSense│ ← Tilted down 10°, front-facing
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│ │ D435i │ Adjustable bracket
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380mm │ ├─────────┤
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│ │ │
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│ │ JETSON │ ← Noctua fan, ventilation slots
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│ │ NANO │
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300mm │ ├─────────┤
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│ │ BNO055 │ ← IMU, vibration-isolated mount
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280mm │ ├─────────┤
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│ │ │
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│ │ ESC + │ ← ESC board + DC-DC converters
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│ │ DC-DCs │
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200mm │ ├─────────┤
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│ │ │
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│ │ BATTERY │ ← Heaviest component, lowest position
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│ │ PACK │ Strapped to spine with velcro
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│ │ │
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80mm │ ├─────────┤
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│ │ BASE │ ← Motor mount plate (6mm)
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│ │ PLATE │
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40mm │ ├────┬────┤
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│ │ │ │
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┴ └────┘ └── 8" wheel (Ø203mm)
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═════════════
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GROUND (0mm)
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Ground clearance: ~40mm (bottom of plate to ground)
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Wheel contact to axle center: ~100mm (8" diameter / 2)
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Axle height from ground: ~100mm
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```
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### 3.3 Front View
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```
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←── 350mm ──→
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┌─────────┐ ─┬─ 550mm
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│ RPLIDAR │ │
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├─────────┤ │
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│ ┃ │ ← spine │
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│ ┃ │ (2020 │
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│ ┃ │ extrusion│
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│ ┃ │ or │
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│ ┃ │ aluminum │
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│ ┃ │ tube) │
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│ ┃ │ │
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├───┃─────┤ │
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┌─────┐ │ ┃ │ ┌─────┐│
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│ │ │ ┃ │ │ ││
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│ 8" │ │ ┃ │ │ 8" ││ 100mm
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│ L │───┤ ┃ ├───│ R ││ (axle)
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│ │ │ ┃ │ │ ││
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│ │ └───┃─────┘ │ │┴─ 0mm
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└─────┘ ┃ └─────┘
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═══════════════════════════════════
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←65→←──── 250mm ────→←65→
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mm (track width) mm
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Total width with tires: ~380mm
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Fits through standard doorway (760mm) ✓
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```
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### 3.4 Spine Detail — Side View
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```
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┌──┐ ← 20×20mm aluminum extrusion (2020 V-slot)
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│ │ or 25×25mm square aluminum tube
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│ │
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│ │──── Shelf bracket (3D printed, bolts to T-slot)
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│ │ Each shelf: 120mm wide × 100-150mm deep
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│ │
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│ │──── Shelf bracket
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│ │
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│ │──── Shelf bracket
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│ │
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│ │──── Shelf bracket
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│ │
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├──┤
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│ │──── Base plate connection (L-brackets, 4x M5)
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└──┘
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Spine length: 470mm (from base plate to LIDAR mount)
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Shelf positions (from base plate):
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0mm — Base plate
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30mm — Battery shelf (holds pack on its side)
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150mm — ESC + DC-DC shelf
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250mm — Jetson Nano shelf
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300mm — BNO055 (attached to spine directly)
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370mm — RealSense bracket (front-facing arm)
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420mm — LIDAR standoff begins
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500mm — LIDAR mount plate
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```
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### 3.5 Wiring Diagram
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```
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BATTERY PACK (35V nominal, 10S Li-ion)
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━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
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│(+) (−)│
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│ │
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├──[E-STOP (NC)]───────────┤
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│ │
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XT60 ├────────┬────────┬────────┤ XT60
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│ │ │ │
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│ ┌───┴───┐ │ │
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│ │DC-DC │ │ │
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│ │36V→5V │ │ │
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│ │ 4A │ │ │
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│ └───┬───┘ │ │
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│ 5V │ │ │
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│ ┌───┴────┐ │ │
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│ │USB Hub │ │ │
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│ │Jetson │ │ │
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│ │RealSns │ │ │
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│ │RPLIDAR │ │ │
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│ └────────┘ │ │
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│ │ │
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│ ┌────┴───┐ │ │
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│ │DC-DC │ │ │
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│ │36V→12V │ │ │
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│ │ 2A │ │ │
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│ └───┬────┘ │ │
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│ 12V │ │ │
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│ ┌───┴────┐ │ │
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│ │LEDs │ │ │
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│ │Speaker │ │ │
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│ └────────┘ │ │
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│ │ │
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┌────┴─────────────────┴────────┴────┐
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│ HOVERBOARD ESC │
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│ (FOC firmware) │
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│ │
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│ I2C: SDA──BNO055──SCL │
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│ UART: TX──Jetson──RX │
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│ │
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│ PHASE L: ─── 8" LEFT MOTOR │
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│ HALL L: ─── (5 wire: hall A/B/C │
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│ + 5V + GND) │
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│ │
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│ PHASE R: ─── 8" RIGHT MOTOR │
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│ HALL R: ─── (5 wire) │
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└────────────────────────────────────┘
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```
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---
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## 4. Phased Build Plan
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### Phase 1: Rolling Skeleton (Days 1-3)
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**Goal:** Prove balance works.
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**Tasks:**
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- [ ] Measure 8" motor axle diameter with calipers
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- [ ] Design motor mount plate in CAD (FreeCAD or TinkerCAD)
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- [ ] Print motor mount plate on Bambu X1C (PETG, 80% infill, ~4h print)
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- [ ] Print axle clamp tops (x2)
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- [ ] Mount both 8" motors to plate
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- [ ] Mount ESC to plate with standoffs
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- [ ] Wire BNO055 to ESC I2C (4 wires: VCC, GND, SDA, SCL)
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- [ ] Wire battery to ESC (XT60)
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- [ ] Modify FOC firmware: add BNO055 I2C read, replace gyro board input
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- [ ] Flash ESC with updated firmware
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- [ ] **SAFETY:** Tie rope from ceiling to plate as fall catch
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- [ ] Power on, tune PID (start with Kp=20, Ki=0, Kd=0, increase gradually)
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- [ ] Achieve stable free-standing balance (no rope)
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**Parts needed:** motor mount plate, 2x clamp tops, M6 bolts, M3 standoffs
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**Risk:** PID tuning can take hours of iteration. Be patient.
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### Phase 2: Spine + Brain (Days 4-7)
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**Goal:** Add Jetson, achieve remote-controlled movement while balancing.
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**Tasks:**
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- [ ] Cut aluminum extrusion/tube to 470mm for spine
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- [ ] Print shelf brackets (4x) and L-brackets for base connection
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- [ ] Assemble spine onto base plate
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- [ ] Mount battery to lowest shelf (velcro straps)
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- [ ] Mount ESC + DC-DC converters
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- [ ] Mount Jetson Nano on shelf, connect 5V power
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- [ ] Wire Jetson UART → ESC UART
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- [ ] Install JetPack 4.6 on Jetson (if not already)
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- [ ] Write serial bridge: Jetson Python → ESC UART commands
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- [ ] Test: keyboard control (WASD) → speed/steer commands → balanced movement
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- [ ] Tune speed response (acceleration limits, max speed for indoor)
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- [ ] Add E-stop button (inline with battery positive)
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**Software deliverable:** `saltylab_teleop.py` — keyboard-controlled balancing bot
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### Phase 3: Eyes + Ears (Days 8-12)
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**Goal:** See the world. Map a room. Detect people.
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**Tasks:**
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- [ ] Print RealSense bracket (adjustable tilt)
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- [ ] Print LIDAR standoff tube + mount plate
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- [ ] Mount RealSense D435i (front-facing, ~10° down tilt)
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- [ ] Mount RPLIDAR A1M8 (top of spine, 360° clear)
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- [ ] Install ROS2 on Jetson
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- [ ] Install and test `realsense-ros` (verify depth stream)
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- [ ] Install and test `rplidar_ros` (verify laser scan)
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- [ ] Run `slam_toolbox` — drive around room, build 2D map
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- [ ] Test person detection with SSD-MobileNet-v2 (TensorRT)
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- [ ] Implement follow mode:
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- Detect person in RGB frame
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- Get distance from depth frame
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- PID to maintain 1.5m following distance
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- LIDAR for obstacle avoidance
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**Software deliverable:** `saltylab_follow.py` — person-following balanced bot
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### Phase 4: Polish + Personality (Days 13-17)
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**Goal:** Make it feel alive. Make it SaltyLab.
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**Tasks:**
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- [ ] Print proper enclosures for all electronics
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- [ ] Print TPU bumpers (front + rear)
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- [ ] Print carry handle
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- [ ] Add NeoPixel LED ring around LIDAR mount (status indication)
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- Blue breathing: idle/balancing
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- Green: following
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- Yellow: exploring/mapping
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- Red: error/low battery
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- [ ] Add small speaker (USB or I2S to amp)
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- Boot sound
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- Acknowledge commands with beeps/chirps
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- Optional: TTS via Jetson ("I see you", "battery low")
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- [ ] WiFi dashboard: live camera feed + map + battery status
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- [ ] Battery voltage monitoring (ADC on ESC → Jetson via UART)
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- [ ] Low battery return behavior (stop and beep)
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- [ ] Integrate with Home Assistant (MQTT: location, battery, status)
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### Phase 5: House Mapping + Autonomy (Days 18-24)
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**Goal:** SaltyLab knows your house.
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**Tasks:**
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- [ ] Map every room (drive around manually, SLAM builds full floor plan)
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- [ ] Save map, set up `nav2` for autonomous navigation
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- [ ] Define waypoints: lab, living room, kitchen, hallway
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- [ ] Patrol mode: visit waypoints on schedule
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- [ ] Person detection + greeting ("hey Tee", "hi Inka")
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- [ ] Integration with Bermuda BLE: know where people are, go to them
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- [ ] Charging dock design (future: auto-dock when low)
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---
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## 5. Speed & Performance Specs
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### Target Performance
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| Parameter | Value | Notes |
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|-----------|-------|-------|
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| Max speed (indoor) | 5 km/h | Software limited for safety |
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| Normal follow speed | 2-3 km/h | Walking pace |
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| Turning radius | 0 (pivot) | Differential drive, spins in place |
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| Ground clearance | 40mm | Clears door thresholds (~15mm) |
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| Max incline | ~10° | Limited by motor torque + balance |
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| Operating time | 3-5 hours | Single 500Wh pack |
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| Charge time | ~2-3 hours | Using one of the existing chargers |
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| Weight | ~7.5 kg | Easy to pick up with handle |
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| Width | 380mm | Fits all doorways |
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| Height | 550mm | Below table height |
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### Motor Specs (8" hub motor, estimated)
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| Parameter | Value |
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|-----------|-------|
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| Nominal voltage | 36V |
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| Rated power | 250-350W per motor |
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| No-load RPM | ~250 RPM |
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| Wheel circumference | ~0.64m (Ø203mm) |
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| Max wheel speed | 160 m/min = 9.6 km/h |
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| Continuous torque | ~2-3 Nm |
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| Stall torque | ~8-10 Nm |
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---
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## 6. Safety Considerations
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| Hazard | Mitigation |
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|--------|-----------|
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| Falls over | TPU bumpers, max tilt cutoff (30°), low CoG |
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| Runs away | Software speed limit (5 km/h), E-stop button |
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| Pinches/crushes | No exposed gears, motor covers |
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| Battery fire | BMS on pack, fused main power, no charging unattended |
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| Hits furniture | LIDAR obstacle avoidance, bumper sensors (future) |
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| Scares the cat | Slow acceleration, no sudden movements |
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---
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## 7. Shopping List (Items NOT in Inventory)
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| Item | Price (CAD) | Source | Notes |
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|------|------------|--------|-------|
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| 2020 aluminum extrusion 500mm | ~$8 | Amazon/AliExpress | Spine |
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| T-slot nuts + M5 bolts (pack) | ~$12 | Amazon | For shelf mounting |
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| M6 bolts + nuts (axle clamps) | ~$5 | Hardware store | 4x sets |
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| NeoPixel ring (24 LED) | ~$8 | Amazon | Status indication |
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| Small speaker + amp (MAX98357A) | ~$10 | Amazon/Adafruit | I2S audio |
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| E-stop mushroom button | ~$5 | Amazon | Safety |
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| XT60 splitter/distribution | ~$8 | Amazon | Power wiring |
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| Misc: heat shrink, zip ties, wire | ~$10 | — | Always need more |
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| **TOTAL** | **~$66** | | Everything else: already owned |
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*Last updated: 2026-02-27*
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*Project: SaltyRover / SaltyLab*
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