Classifies facial expressions into neutral/happy/surprised/angry/sad
using geometric rules over MediaPipe Face Mesh landmarks — no ML model
required at runtime.
Rules
-----
surprised: brow_raise > 0.12 AND eye_open > 0.07 AND mouth_open > 0.07
happy: smile > 0.025 (lip corners above lip midpoint)
angry: brow_furl > 0.02 AND smile < 0.01
sad: smile < -0.025 AND brow_furl < 0.015
neutral: default
Changes
-------
- saltybot_scene_msgs/msg/FaceEmotion.msg — per-face emotion + features
- saltybot_scene_msgs/msg/FaceEmotionArray.msg
- saltybot_scene_msgs/CMakeLists.txt — register new msgs
- _face_emotion.py — pure-Python: FaceLandmarks, compute_features,
classify_emotion, detect_emotion, from_mediapipe
- face_emotion_node.py — subscribes /camera/color/image_raw,
publishes /saltybot/face_emotions (≤15 fps)
- test/test_face_emotion.py — 48 tests, all passing
- setup.py — add face_emotion entry point
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.