Maximising Arduino Raspberry Pi ESP32 I/O with MCP23017 I2C GPIO Expander | eBay
Tutorial: Maximising your Arduino's I/O ports with MCP23017 | tronixstuff.com
Amazon.com: Waveshare MCP23017 IO Expansion Board I2C Interface Expands 16 I/O Pins Stack to 8 pcs Used at The Same Time Allow Multi I2C Modules to be Stacked : Electronics
MCP23017 Arduino Example Tutorial - Easily Add More GPIO Pins!
Adding Digital I/O To Your CircuitPython Compatible Board: Part 3 - The MCP23017 - Woolsey Workshop
MCP23017 problem - General Electronics - Arduino Forum
MCP23017: Have you run out of I/O? This chip is the answer!
MCP23017 scheda di espansione I/O bidirezionale a 16 bit con modulo di interfaccia seriale I2C compatibile con Arduino