Arduino-based barometric altimeter / altitude deviation alerter

While working on my instrument training, it occurred to me that I had everything I needed in my parts bin to build a device to help alert me to deviations in altitude. So, I built MonkeyAltimeter.

It started off on a breadboard while I worked on the code:

Then, I took it for a flight test (primarily to see how accurate it was in the cabin and see if my VSI routine worked):

Finally, I designed and printed a simple case for it:

The details,  parts list, operation manual, &etc are here:
http://www.thingiverse.com/thing:942832

The source code is here:
https://github.com/phreakmonkey/MonkeyAltimeter


Enjoy!