sl-jetson
22aaeb02cf
STM32 firmware (C): - include/jetson_cmd.h: protocol constants (HB_TIMEOUT_MS=500, SPEED_MAX_DEG=4°), API for jetson_cmd_process/is_active/steer/sp_offset - src/jetson_cmd.c: main-loop parser for buffered C<spd>,<str> frames; setpoint offset = speed/1000 * 4°; steer clamped ±1000 - lib/USB_CDC/src/usbd_cdc_if.c: add H (heartbeat) and C (drive cmd) to CDC_Receive ISR — follows existing pattern: H updates jetson_hb_tick in ISR, C copied to jetson_cmd_buf for main-loop sscanf (avoids sscanf in IRQ) - src/main.c: integrate jetson_cmd — process buffered frame, apply setpoint offset around balance_update(), inject steer into motor_driver_update() only when heartbeat alive (fallback: steer=0, setpoint unchanged) ROS2 (Python): - saltybot_cmd_node.py: full bidirectional node — owns serial port, handles telemetry RX → topics AND /cmd_vel TX → C<spd>,<str>\n + H\n heartbeat 200ms timer; sends C0,0\n on shutdown; speed/steer_scale configurable - serial_bridge_node.py: add write_serial() helper for extensibility - launch/bridge.launch.py: mode arg (bidirectional|rx_only) selects node - config/bridge_params.yaml: heartbeat_period, speed_scale, steer_scale docs - test/test_cmd.py: 13 tests — zero, full fwd/rev, turn clamping, combined - setup.py: saltybot_cmd_node entry point All 21 tests pass (8 parse + 13 cmd). 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.