It's simply a 12 volt CPU fan, a magnet from a fried hard drive, a potentiometer (rheostat/dimmer/thingy that makes it spin slower) and a 5 volt power supply from an old Palm Pilot charger. The only thing I had to buy was the potentiometer, and it was around $4.
the magnet should probably be glued down but it is attracted to the fan magnet, so it stays in place just fine.
for the wiring, the positive off the power supply (black w/ white strip, but you can't see that in the pic) goes to the left post and the negative goes straight to the negative (black) wire on the fan. The positive from the fan goes to the middle post.
I bought 2 spinner bars.
A 1.5 inch hexagon with a ridge in the middle (mine's red)
and a cross/plus sign
The plus seems to do a better job than the round stir bar and is also much quieter. The round stir bar does a lot of vibrating but the plus is barely audible. I've only tried water so far, I need to see how 2 liters of starter will spin with it.
