This video explains about I2C, with an example of using the I2C extender chip number PCF8574
This extender is used also in Arduino LCD with buttons that is sold on the net
Links Amazon:
Buy on Amazon Arduino Mega: Amazon Mega
Buy on Amazon Arduino Uno: Amazon Uno
Buy on Amazon Arduino Nano: Amazon Nano
Buy on Amazon Arduino 33 IOT: Amazon 33 IOT
Buy on Amazon Arduino Nano ESP32: Amazon Nano Esp32
Links Aliexpress:
Buy on Aliexpress Arduino Mega: Aliexpress Mega
Buy on Aliexpress Arduino Uno: Aliexpress Uno
Buy on Aliexpress Arduino Nano: Aliexpress Nano
Buy on Aliexpress Arduino 33 IOT: Aliexpress 33 IOT
Buy on Aliexpress Arduino Nano ESP32: Aliexpress Nano esp32
Links Ebay:
Buy on Ebay Arduino Mega: Ebay Mega
Buy on Ebay Arduino Uno: Ebay Uno
Buy on Ebay Arduino Nano: Ebay Nano
Buy on Ebay Arduino 33 IOT: Ebay 33 IOT
Buy on Ebay Arduino Nano ESP32: Ebay Nano esp32