Quick plans for creating a USB to barrel plug power adapter.

While you can buy a cheap solution for this problem I'd encourage you to recycle some of your spare parts and make your own.

You can easily make your own USB power cable using a 2.1mm barrel connector and a USB Type A host cable.

The center of the barrel plug is DC_5V and the sleeve is GND. This matches quite nicely with the USB Pin 1 (DC_5V) and USB Pin 4 (GND). I will create a simple diagram and post it later today.