asi: Skill for Claude Code

Cyton Dongle

USB wireless receiver (RFD22301/RFDuino) for OpenBCI Cyton 8/16-channel EEG board.

Hardware

• Dongle: FTDI FT231X USB-UART → RFDuino 2.4 GHz radio
• Serial: 115200 baud, 8N1
• Device: /dev/cu.usbserial-* (macOS) or /dev/ttyUSB* (Linux)
• Sample Rate: 250 Hz
• Channels: 8 (Cyton) or 16 (Cyton + Daisy)
• Packet: 33 bytes (0xA0 start, 24 bytes channel data, 6 bytes aux, 1 byte counter, 0xC0 stop)

First-Time Pairing (Critical)

A new dongle and board are typically on different radio channels. The standard 0xF0 0x01 channel-set command requires both sides to handshake — it fails when they're on different channels.

Use 0xF0 0x02 (CHANNEL_SET_OVERRIDE) to force the dongle to each channel without requiring board response, then check system status:

import serial, time

ser = serial.Serial('/dev/cu.usbserial-XXXXX', 115200, timeout=2)
time.sleep(2)

for chan in range(26):
    ser.reset_input_buffer()
    ser.write(bytes([0xF0, 0x02, chan]))  # override dongle (no handshake)
    time.sleep(0.5)
    ser.read(ser.in_waiting or 512)

    ser.reset_input_buffer()
    ser.write(bytes([0xF0, 0x07]))        # system status query
    time.sleep(0.5)
    resp = ser.read(ser.in_waiting or 512).decode('utf-8', errors='ignore')

    if 'System is Up' in resp:
        print(f'FOUND BOARD ON CHANNEL {chan}')
        break
    else:
        print(f'Ch {chan}: Down')

ser.close()

Radio Commands (0xF0 prefix)