sl-controls
7d09c8c814
Implements node watchdog ROS2 node that monitors heartbeats from critical systems and triggers safety fallback when motor driver is lost >2s. Features: - Monitor heartbeats from: balance, motor_driver, emergency, docking - Alert on /saltybot/node_watchdog (JSON) if heartbeat lost >1s - Safety fallback: zero cmd_vel if motor driver lost >2s - Republish cmd_vel on /saltybot/cmd_vel_safe with safety checks - 20Hz monitoring and publishing frequency - Configurable heartbeat timeout thresholds Heartbeat Topics: - /saltybot/balance_heartbeat (std_msgs/UInt32) - /saltybot/motor_driver_heartbeat (std_msgs/UInt32) - /saltybot/emergency_heartbeat (std_msgs/UInt32) - /saltybot/docking_heartbeat (std_msgs/UInt32) - /cmd_vel (geometry_msgs/Twist) Published Topics: - /saltybot/node_watchdog (std_msgs/String) - JSON status - /saltybot/cmd_vel_safe (geometry_msgs/Twist) - Safety-checked velocity Package: saltybot_node_watchdog Entry point: node_watchdog_node Launch file: node_watchdog.launch.py Tests: 20+ unit tests covering: - Heartbeat reception and timeout detection - Motor driver critical timeout (>2s) - Safety fallback logic - cmd_vel zeroing on motor driver loss - Health status JSON serialization - Multi-node failure scenarios Co-Authored-By: Claude Haiku 4.5 <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.