IxpandO is an input/output expansion board based on Microchip’s MCP23017, BoldportClub Project #16. The board design leaves the door open for various configurations. I decided to go initially with the default setup of 8 inputs (switches) and 8 outputs (LEDs), with an Arduino sketch to demonstrate digital output and interrupt-driven input. As always, all notes, schematics and code are in the Little Electronics & Arduino Projects repo on GitHub