I am trying to make a device that can be powered by a 9V battery. Because I don’t want the battery to be drained constantly, I want the device to be able to be plugged in as an option.
I also do not want the arduino to turn off as it will be running a timer. The main purpose of the device is to be an hourly timer.
If I plug the Ardiuno Uno in via usb, will it ignore the 9V, and not drain the battery? Is there a simple way to keep the arduino on while switching power sources?