saltybot_bridge ROS2 Python package (ament_python):
- serial_bridge_node.py: reads USB CDC JSON telemetry from STM32F722 at 50Hz
Parses exact firmware format: {"p","r","e","ig","m","s","y"} (all ×10 ints)
State enum: 0=DISARMED, 1=ARMED, 2=TILT_FAULT (matched to balance_state_t)
- Publishes sensor_msgs/Imu on /saltybot/imu (pitch/roll/yaw as angular_velocity)
- Publishes std_msgs/String on /saltybot/balance_state (full PID JSON diagnostics)
- Publishes diagnostic_msgs/DiagnosticArray on /diagnostics (OK/WARN/ERROR by state)
- Auto-reconnects on serial disconnect; IMU fault frames → ERROR diagnostic
- launch/bridge.launch.py with serial_port + baud_rate launch args
- config/bridge_params.yaml (921600 baud, /dev/ttyACM0)
- test/test_parse.py: 8 unit tests covering normal, fault, edge cases (all pass)
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
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
docs/pinout.md— GPIO/I2C/UART pinout for all peripheralsdocs/power-budget.md— 10W power envelope analysis
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.