This project is a number of years old but it is a great resource. Full schematics and code are provided so that you too can enjoy building an altimeter for your rocket.

“I’ve been interested in model rocketry for a long time, but as my interest in electronics became stronger and more developed, rockets fell by the wayside. Recently, though, I thought of a way that I could combine these two interests: try to put electronic devices onboard rockets! That is what I have been trying to do recently with my BTSAM project, and just this month, with the Rocket Altimeter Project.

The final design used a Parallax Basic Stamp II (because of its internal EEPROM which could be used for datalogging, and because we wanted to use Basic as the programming langage), an AD7706 16-bit Sigma-Delta analog to digital converter, a Zetex ZRC250 2.5V reference, a National Semi. LP2950 low-dropout 5V regulator, and an ADXL190 +/- 80 g MEMS accelerometer. Analog Devices was good enough to give us two each of the ADC and accelerometer free as samples.”