Tinkering with my 3D printer has taught me a lot about small electronics, but it's all been very specific to this one application. I wanted a better understanding of circuits, resistors, capacitors, etc... and how they work on a very basic level. So I picked up an Arduino and a bunch of components, and that's kept me well occupied for the last few weeks. So far the Arduino's been tethered to a computer to get power from the USB port. That's been ok for now, but I have a fe