Arduino Shield - Stepper Driver and Digital Caliper Reader ver.3

This is my 3rd full revision of a board I am making for another project. I thought I should post the schematic/layout incase anyone else finds it useful. I am getting faster at this layout stuff. The first was so painful but I am starting to get the strategy down.

The board uses an H bridge to drive a small stepper motor. The power for the stepper is fed of the Vin pin of the arduino. So to run this you will need a 9-12v power supply feeding into the Arduino barrel jack. I have made capacity for two calipers (To measure X and Y simultaneously).

Design is based on the schematic at http://arduino.cc/en/Reference/StepperBipolarCircuit and the Nerd kit DRO tutorial. http://www.nerdkits.com/videos/digital_calipers_dro/

Check out those sites for backround reading and code.

Check back here later for build photos and my code.

Check back here much later to see the circuit in a useful application.

https://docs.google.com/file/d/0B8_hXvCtBTMMUXVFQWN4RkVTQkE/edit