sl-perception
131d85a0d3
Add saltybot_safety_zone — ROS2 Python node that processes the RPLIDAR
A1M8 /scan into three concentric 360° safety zones, latches an e-stop
when DANGER is detected in the forward arc, and overrides /cmd_vel to
zero while the latch is active.
Zone thresholds (default):
DANGER < 0.30 m — latching e-stop in forward arc
WARN < 1.00 m — advisory (published in sector data)
CLEAR otherwise
Sector grid:
36 sectors of 10° each (sector 0 = robot forward, CCW positive).
Per-sector: angle_deg, zone, min_range_m, in_forward_arc flag.
E-stop behaviour:
- Latches after estop_debounce_frames (2) consecutive DANGER scans
in the forward arc (configurable ±30°, or all-arcs mode).
- While latched: zero Twist published to /cmd_vel every scan + every
incoming /cmd_vel_input message is blocked.
- Clear only via service (obstacle must be gone):
/saltybot/safety_zone/clear_estop (std_srvs/Trigger)
Published topics:
/saltybot/safety_zone String/JSON every scan
— per-sector {sector, angle_deg, zone, min_range_m, forward}
— estop_active, estop_reason, danger_sectors[], warn_sectors[]
/saltybot/safety_zone/status String/JSON 10 Hz
— forward_zone, closest_obstacle_m, danger/warn counts
/cmd_vel Twist zero when e-stopped
Subscribed topics:
/scan LaserScan — RPLIDAR A1M8
/cmd_vel_input Twist — upstream velocity (pass-through / block)
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.