Power Supply
On the breadboard, there are rows of connectors for positive supply voltage and ground.
Ground on the breadboard should be connected to a ground on the Arduino.
If you are using a separate power supply for the breadboard, don't connect the positive power supply
voltage to the Arduino. But if the breadboard doesn't have its own power supply, connect the positive
row to the +5 pin of the Arduino. Some Arduinos use 3.3V. Check details on the Arduino site for them.