This is my Raspberry Pi Zero control board for vPiP (Whats vPiP? Its a hanging v plotter control software written in Python and Arduino firmware - it can probably be used for other drawing machines, but its main purpose in life is for use with the vPiP software - https://github.com/brianinnes/vpip).
What's a hanging v plotter? Its a drawing machine where a pen is suspended from two strings or chains attached to two motors at the top outer corners of the machine. The pen is moved by lengthening or shortening the strings or chains with the motors.
The hardware is based on http://www.thingiverse.com/thing:1394948 but includes a DCtoDC PSU that should in theory power the Pi as well as everything else.
This is a work in progress, has little in the way of circuit protection, is untested and is more than capable of letting the magic smoke out of your Raspberry Pi so use at your own risk or wait until i've killed some boards and fixed all the problems!
Files are on github - will update this when its tested.