With this sketch you can control pins of a remote Arduino board through ESPHome. The Arduino acts as a port expander, allowing you to use more pins than a standard ESP8266/ESP32 has. The Arduino is ...
Arduino library for I2C MCP23017 16 channel port expander - quiknick/MCP23017_NK ...
A while ago I received a couple of I/O port expander modules that use the I 2 C protocol. Using that Chinese module, you can use only the SDA and SCL pins of your Arduino, or any microcontroller ...