I've been working on a dogie door for a while - while the software is straightforward, finding a suitable motor controller has been more difficult.
The problem is that a lot of the inexpensive motor control shields are just too meager to control anything but the most dinky motors. ladyada's Arduino shield only does 600mA continuous, 1.1A peak . Pololu makes beefier motor controllers, the DMC 01 can do 13 amps, but it's pretty expensive (about $100).
So I've been on the lookout for a high power, inexpensive, and easy to control circuit - I was flipping through starlino's website and I spotted exactly what I was looking for. His idea is pretty simple: why not combine 2 motor controller IC's to split the load?
He calls the circuit the 'OctoDriver', it combines 2 h-bridges to provide 8 amps peak, 4 amps continuous. I asked him if I could put it on a PCB, and he thought it was a great idea. I couldn't think of a better name, so I call my version "The OctoDriver".
I also put it on a Propeller Platform compatible footprint, so it can be used on a breadboard, perfboard or with a Propeller microcontroller. The design is available under the MIT license, so anyone is free to hack away.
The OctoDriver is also available as a kit from Gadget Gangster.
Flip to the next step and I'll give you some more technical details on the OctoDriver and show you how to use it.