Hardware Interface Subsystem

1. Role

The Hardware Interface subsystem provides the low-level communication and control for the Huenit robotic arm via a serial (USB) G-code interface.

2. Key Components

• Serial Interface: Communication occurs over /dev/cu.usbserial-310 at 115200 baud.
• G-code Controller: huenit_svg.py and huenit_draw.py parse SVG or shape commands into G-code for the arm's onboard controller.
• Z-axis Control: Manages pen-up (Z_UP=6.0mm) and pen-down movements.
• Tilt Correction: TILT_SLOPE in huenit_svg.py provides Z-height correction per mm of Y travel, indicating the drawing surface may not be perfectly level.

3. Calibration

• Required: Must be run at the start of each session.
• Tool: huenit_draw.py calibrate
• Output: Generates calibration.json in the huenit skill directory.

4. Notes and Open Points

• Calibration Persistence: Code checks for /tmp/huenit_ready.flag. Since /tmp is cleared on reboot, calibration must be performed every session. However, some documentation implies a more permanent state could be achieved.
• Safety: The arm's G-code parser does not appear to have complex obstacle avoidance. It relies on the user ensuring the drawing area (125mm x 125mm) is clear.

Sources:

• ~/.openclaw/workspace/skills/huenit/huenit_svg.py
• ~/.openclaw/workspace/skills/huenit/huenit_draw.py
• AGENTS/CONTEXT/robot_ross_artist.md