Description

You're lack of inputs/outputs on your electronic editing, and there's enough pine for an I2C link. This circuit MCP23017 will you peremettre to add 16 inputs or outputs GPIO with only two wires to connect I2C. Each GPIO can be configured as pullup or open drai programmatically.

The cirduit runs between 2, 7V and 5, 5V, which allows compatibility with logic 3, 3V and 5V without risk. It is possible to exit 20mA on each output to power a LED for example.

I2C addresses are configurable via 3-wire ADR0 to ADR2, which allows to put 8 MCP23017 on the same line I2C, making the total 128 exit GPIO!

Documentation

Arduino library: Adafruit-MCP23017-Arduino-Library