arduino I2C Communication
Introduction
I2C is a communication protocol that can make two or more Arduino boards talk to each other. The protocol uses two pins - SDA (data line) and SCL (clock line). Those pins are different from one Arduino board type to another, so check the board specification. The I2C protocol set one Arduino board as the master, and all the others as a slave. Each slave has a different address that the programmer set hard-coded. Remark: Make sure all boards connected to the same VCC source
