The purpose of this project is to create a 9v external battery power supply for the Arduino Uno.



  1. Cardboard
  2. x1 – Switch
  3. x1 – LED (any color)
  4. x1 – Wires
  5. x1 – 2.1mm Male Plug
  6. x1 – 9v Battery Holder
  7. x1 – Soldering Iron & Solder

external battery power supply


For my thoughts and comments, see this post.


9v power supply - schematic

-The pink box is the 2.1mm Male Plug that connects to the Arduino.-
*note: the output of the 2.1mm male plug is 6.5v

My Project