sl-jetson ea26cda76a feat(bridge): battery management node (Issue #125)
Add battery_node.py:
- Subscribes /saltybot/telemetry/battery (JSON from stm32_cmd_node)
- Publishes sensor_msgs/BatteryState on /saltybot/battery at 1 Hz
- SoC source priority: STM32 fuel gauge soc_pct field → fallback to
  3S LiPo voltage curve (12-point lookup with linear interpolation)
- Charging detection: current_ma < -100 mA threshold
- Alert levels: WARNING (20%)→speed 60%, CRITICAL (10%)→speed 30%,
  EMERGENCY (5%)→zero /cmd_vel + /saltybot/arm(False) disarm
- /saltybot/battery/alert JSON topic on threshold crossings
- /saltybot/speed_limit Float32 (0.0-1.0) for nav speed capping
- SQLite history logging: /var/log/saltybot/battery.db, 7-day retention
- Hourly prune timer to keep DB bounded

Add test_battery.py (70+ tests, no ROS2 runtime):
- SoC lookup: all curve points, interpolation, clamping, 3S/4S packs
- Alert level thresholds and transitions for all levels
- Speed factor assignments per alert level
- Charging detection logic
- sensor_msgs/BatteryState field population
- SQLite insert/retrieve/prune (in-memory and on-disk)
- JSON telemetry parsing: normal, charging, soc_pct=0 fallback

Add battery_params.yaml, battery.launch.py.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
2026-03-02 09:27:06 -05:00
..

Jetson Nano — AI/SLAM Platform Setup

Self-balancing robot: Jetson Nano dev environment for ROS2 Humble + SLAM stack.

Stack

Component Version / Part
Platform Jetson Nano 4GB
JetPack 4.6 (L4T R32.6.1, CUDA 10.2)
ROS2 Humble Hawksbill
DDS CycloneDDS
SLAM slam_toolbox
Nav Nav2
Depth camera Intel RealSense D435i
LiDAR RPLIDAR A1M8
MCU bridge STM32F722 (USB CDC @ 921600)

Quick Start

# 1. Host setup (once, on fresh JetPack 4.6)
sudo bash scripts/setup-jetson.sh

# 2. Build Docker image
bash scripts/build-and-run.sh build

# 3. Start full stack
bash scripts/build-and-run.sh up

# 4. Open ROS2 shell
bash scripts/build-and-run.sh shell

Docs

Files

jetson/
├── Dockerfile              # L4T base + ROS2 Humble + SLAM packages
├── docker-compose.yml      # Multi-service stack (ROS2, RPLIDAR, D435i, STM32)
├── README.md               # This file
├── docs/
│   ├── pinout.md           # GPIO/I2C/UART pinout reference
│   └── power-budget.md     # Power budget analysis (10W envelope)
└── scripts/
    ├── entrypoint.sh       # Docker container entrypoint
    ├── setup-jetson.sh     # Host setup (udev, Docker, nvpmodel)
    └── build-and-run.sh    # Build/run helper

Power Budget (Summary)

Scenario Total
Idle 2.9W
Nominal (SLAM active) ~10.2W
Peak 15.4W

Target: 10W (MAXN nvpmodel). Use RPLIDAR standby + 640p D435i for compliance. See docs/power-budget.md for full analysis.