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Adafruit 15×7 CharliePlex

The Adafruit 15×7 CharliePlex LED Matrix FeatherWing is a compact monochrome green LED display driven by the IS31FL3731 controller. It communicates over I2C and provides a 15×7 pixel grid suitable for scrolling text, simple icons, and status indicators.

CyberHUD provides a single panel definition for this board.

Quick Start

sudo ./cyberhudd -panel adafruit-15x7-charlieplex

In your /etc/cyberhudd.json:

{
  "display": {
    "panel": "adafruit-15x7-charlieplex"
  }
}

Display Characteristics

Property Value
Resolution 15 × 7 pixels
Color format Monochrome (green LED)
Controller IS31FL3731
Interface I2C
Input None

Troubleshooting

CyberHUD emits detailed diagnostic logs during panel initialization. Check them with:

sudo journalctl -u cyberhudd.service -n 50

Common Issues

Symptom Likely Cause Fix
i2c device ... open=error I2C not enabled on the Raspberry Pi Run sudo raspi-config → Interface Options → I2C → Enable, then reboot
No LEDs light up but no error logged Wrong I2C address or loose connection Verify wiring and run i2cdetect -y 1 to confirm device appears at address 0x74
LEDs flicker or display corrupts I2C bus noise or insufficient pull-ups Use short wires, verify 3.3V supply is stable, and ensure I2C pull-up resistors are present