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

Adafruit GPS shield

I finished building the Adafruit GPS shield. I did a quick test whilst I commuted back to my flat. The visualisation generator I used is at every trail here:

http://www.everytrail.com/view_trip.php?trip_id=1927731


http://www.gpsvisualizer.com/ is another site that does the same thing.

What I dont like about the module is that you have to take out the SD card to load the data into the computer. It would be great if the data could be accessed throught the serial port. I have started writing some code that allows you to manipulate files on the SD card with some basic menus over serial. However, I am having trouble erasing files. If you have any tips, please let me know.


I also want to add some triggering options to the GPS module. I want to do this to A) reduce power consumption B) reduce data density.

The plan is:
A mode switch allow you to select. 1.trigger mode (push button/external trigger ie camera) 2. Normal mode, sampling at the normal rate. 3. Interval timing timing is set by a potentiometer that allows for logarithmic interval timing. The idea here is to save power where possible.