OpenArm KER

A teleoperation system for OpenArm robots using KER (Kinematic Equivalent Replica).

Features

• Joint mapping: Flexible configuration-based mapping from leader to follower joints
• USB communication: Interface with M5Stack CoreS3 via USB vendor mode

Quick Start

1. Install system dependencies

sudo apt install libusb-1.0-0-dev

2. Set up udev rules (run once)

USB vendor mode only (normal use):

echo 'SUBSYSTEM=="usb", ATTRS{idVendor}=="303a", MODE="0666"' | sudo tee /etc/udev/rules.d/99-m5stack.rules
sudo udevadm control --reload-rules && sudo udevadm trigger

If you also want to flash firmware (adds stable device name /dev/m5_ker_485):

Put M5Stack into flashing mode (hold RST 3 seconds until green LED lights up), then run:

SERIAL=$(udevadm info -q property -n /dev/ttyACM0 | grep ID_SERIAL_SHORT | cut -d= -f2)
sudo tee /etc/udev/rules.d/99-m5stack.rules << EOF
# USB vendor mode (normal operation)
SUBSYSTEM=="usb", ATTRS{idVendor}=="303a", MODE="0666"

# Serial mode (flashing) with stable device name
SUBSYSTEM=="tty", ATTRS{idVendor}=="303a", ATTRS{idProduct}=="1001", ATTRS{serial}=="$SERIAL", MODE="0666", SYMLINK+="m5_ker_485"
EOF
sudo udevadm control --reload-rules && sudo udevadm trigger

Press RST once to reboot normally.

3. Install

uv pip install openarm_ker

4. Connect M5Stack and verify

Plug the M5Stack CoreS3 into your PC via USB and run:

openarm-ker-cli ping

Expected output:

{
  "fw": "v1.0.0",
  "hw": "KER-v1.0.0",
  "updated": "2026-05-25"
}

5. Sample usage

from openarm_ker import KERStream

with KERStream(transport="usb") as stream:
    data = stream.latest()
    if data is not None:
        ts      = data["timestamp"]
        angles  = data["angles"]
        enc_val = data["encoder_value"]
        enc_btn = data["encoder_button"]
        angles_str = " | ".join([f"CH{i+1:02d}: {a:8.2f}°" for i, a in enumerate(angles)])
        print(f"TS: {ts:10d} | {angles_str} | ENC: {enc_val:4d} (Btn: {int(enc_btn)})", end='\r')

CLI

# Check device connection and fetch schema
openarm-ker-cli ping

# Stream raw data to terminal
openarm-ker-cli stream

# Serial transport
openarm-ker-cli stream --transport serial --port /dev/m5_ker_485 --baud 2000000

Related Links

• 📚 Read the documentation
• 💬 Join the community on Discord
• 📬 Contact us through openarm@enactic.ai

License

Licensed under the Apache License 2.0. See LICENSE.txt for details.

Copyright 2026 Enactic, Inc.

Code of Conduct

All participation in the OpenArm project is governed by our Code of Conduct.