Documentation

1.0 Keypad

The kepad is driven by an io-expander. Thus it can be acessed over i2c. Adress 0x21

1.1 Wiring

• Red: 3.3V
• Black GND
• Green SDA -> D3
• Grey SCL -> D4

2.0 LCD

The LCD display is driven on the same i2c bus as the keypad.