Power? We always need more power! Many months back Joel had an old computer power supply that he modified to use as a cheapo bench power supply. Sure, it doesn’t have all the bells and whistles (and adjust-ability) of a real bench power supply, but since we hate to waste, and love to recycle, it’s a good use of an old power supply.
I learned a lot about power supplies last month when I destroyed the one I use(d) with my RepRap, and in the process I ended up harvesting a few PSUs from old computers we had in the server room at work. I ended up using one of them to build my own project power supply with 5 volt and 12 volt outputs. I grabbed a pair of resistors from the component library to put a load on the supply, and drilled four holes in the case to mount a few posts I got at Radio Shack. I’ve now got plenty of power to power all sorts of powerful projects!
Here you can see it powering up an LED ring light that requires 12 volts. I can also use it to run a small fan when soldering components. The uses for such a power supply are endless! (Well, within the supplied voltage and current anyway.)