Stepper motor controllers

Does anyone know where I can buy some bipolar stepper motor controllers and an H-bridge in one package? Or even better, schematics/pcb layout of a driver board?

UPDATE:
Does anybody have any experience with the Easy Driver? It seems like a cheap alternatives to some of the other available controllers, but I just want to know if you get what you pay for.

westfw9 years ago
AVRSTMD an open source bipolar stepper driver controller by an Atmel AVR. $85 assembled, assorted kitting options ($10 for a bare PCB.)
guyfrom7up9 years ago
Ok here we go

---0000-----
|xxxxxxxxx|
|-----x-----|

the 0's are the coil,
the bottom thing is the spark gap, the x's are nothing, just a thing so it shows up right on instructbles, the ---- and | ar wires. The x in the bottom middle is the tiny gap for the spark. Hook up the coil to the capacitors as normal
guyfrom7up9 years ago
trackin me down, eh ;) Whenever it sparks it's not the energy coming from the capacitor (well it is, but indirectly). whenever you suddenly remove current from a coil it produces something like a kickback (it's called EMF) and the voltage is higher than the input was. For example, 300 volts into a coil, quickly removed, 1500 volts might come rushing back in reverse polarity. Obviously that's really bad for the capacitors and charging circuits etc. it takes about 30,000 volts for every centimeter for the electricity to spark. so you probably want the wires for the spark gap about 1mm apart, which'll take 3,000 volts to jump. The emf might produce that, but I dunno how to calculate it. Ask tech-king maybe.
guyfrom7up9 years ago
Google PicStep I made some of those, havn't tested it yet cause I have to build some of my other stuff.