This is a basic project for Arduino – an expansion of the Blink sketch included with the Arduino software.  You don’t need many parts for this:

  • 1 – 5mm red LED
  • 1 – 5mm green LED
  • 2 – 220R resistors
  • 1 – jumper wire
  • 1 – breadboard (I used a 170-point mini board for this)

The flat (-) sides of the LEDs will be connected to ground.  The rounded (+) sides will be connected to 220R resistors which are in turn connected to pins 12 (green) and 13 (red) on your Arduino Uno.




You can power this either via USB (convenient if you’re making changes to code) or via battery.  I use a 9V battery connected to a barrel plug.


For the Fritzing file and the Arduino code, please visit this project’s page on