Implements ambient-light-aware night vision mode for the D435i + IMX219
stack on the Jetson Orin Nano Super:
• light_analyser.py — histogram-based intensity FSM with hysteresis:
day → twilight → night → ir_only
• camera_controller.py — D435i IR emitter via realsense2_camera param
service + IMX219 gain/exposure via v4l2-ctl
• gpio_headlight.py — physical pin 33 headlight; Jetson.GPIO PWM
primary, sysfs on/off fallback, sim mode
• light_monitor_node.py — subscribes IMX219/IR1, publishes
/saltybot/ambient_light + /saltybot/vision_mode
• night_vision_controller_node.py — reacts to mode changes; drives
D435i emitter, IMX219 gain, headlight
• ir_slam_bridge_node.py — mono8 IR1 → rgb8 republish so RTAB-Map
keeps loop-closing in darkness
• launch/night_vision.launch.py + config/night_vision_params.yaml
• test/test_night_vision.py — 18 unit tests (18/18 pass, no ROS2 needed)
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.