Arduino Power Unit
I needed an uninterruptible power supply for an Arduino Microcontroller. I wanted the Arduino to be powered by a 9V wall adapter with a backup 9V battery. When AC power is available the unit will draw power from the wall adapter, if there is a power cut the unit will seamlessly switch to the battery as a power source and back when power is available. I wanted various indicator lights as well such as during a power cut an LED…