When hooking up Arduino boards that have SDA and SCL pins labelled, used these pins for I 2 C, otherwise, when no such labels exist, use pins 4 and 5. As per diagram, both boards use the same ground.

The power supply can be connected to the Arduino Uno by plugging into the power jack of the Arduino board. You can also use connect to the Vin pin and the GND pin of the POWER connector. The suggested ...