I need more power, Scotty!

School's winding down for the mermals. For Dragonfly, my high school student, this means finals. Even for Wolf Bait, my eighth grader, there are projects to finish. The only thing he's building right now is a model of Gutenberg's press for extra credit. Not content to sit idle, mermaldad had to tinker with something. Besides, if we're going to build a motor controller, we're going to need a good power supply to test the circuit with. Sure, a couple of batteries would be easier, but no one ever accused me of taking the easy route (even when it makes sense).

So let's adapt a power supply. I found a nice website at http://web2.murraystate.edu/andy.batts/ps/powersupply.htm which describes turning a PC power supply into a hobby supply. I already had a PC power supply laying around, given to me by a friend. Even better, it already had a switch and cooling fan built in. So all I really needed was to connect the power feeds to some binding posts and hook in a load resistor (switching mode power supplies must have a load). I left the unused power connectors in case I ever need them to test out computer components. Here's a picture of the finished power supply:



Here's a close up of the binding posts area. The label on the power supply conveniently had the four supply voltages arranged such that I could put a binding post next to each one. The cable tie holds the load resistor against the case for heat transfer.



Hmm. I suppose it would've been smart to be sure the power supply works before doing all these modifications, wouldn't it?