I was fascinated by the possibilities of a RepRap, being able to produce 3-D objects on your own machine.
Building a RepRap was a nice challenge because it incorporates all kinds of skills, mechanical construction, electronics and software.
For an overview of the possibilities and community see the RepRap wiki site.
There are various electronics around but they -almost- all depend on the polulu stepper drivers (see StepStick a Polulu stepper replacement), since the electronics is a substantial part of the cost I looked for alternatives and found it in the Toshiba TB6560 chip, which currently is cheap on ebay.

The overall solution in using the Arduino Mega as processing platform with a shield containing the power drive for the stepper engines is appealing so this design is based on the current version of the RAMPS (Reprap Arduino Mega Polulu Shield).

The photos are of the first version of the PCB, the second version corrects some minor mistakes and gives more possibility for tuning the motor currents and extra space for the connectors.