I ran across this the other day and I think I am going to build it soon. It has a ton of functions from volt meter to cap tester to PWM. It would be increadibly cheap to build (Esp. if you go to microchip.com and get the pic for free) and could be used to test stepper drivers and about everything else. It also outputs a NTSC pattern to test tv's. http://www.mondo-technology.com/ choose SuperProbe on the right hand. Then choose to go to the hall of fame and then go to the spanish one. or just go here http://heli.xbot.es/SuperProbe/SuperProbe.htm but you might have to translate it.