A quick update as of 25 December 2008. The circuit board artwork is out for fab!
A quick update as of 16 December 2008. The ARM7-based 'AltusMetrum' design has been shelved indefinitely. Working with Keith Packard, I recently embarked on a complete redesign based on the TI cc1111. We got there by deciding we need a low-power RF beacon for post-landing direction finding, learning of the existence of this part, then realizing that we could radically simplify things by using it as the basis for a completely new avionics design. The cc1111 integrates a full 70cm transceiver, 8051 processing core, and peripherals on one chip. We add to that a barometric sensor, temperature sensor, accelerometer, eeprom memory, and full LiPo battery support powered by a USB interface also used for configuration and post-flight data extraction. It looks like we can get all the features we want on a single board for less than the price of most commercial altimeter boards, with the only downside being dramatically reduced processing power. We have a complete schematic and a first pass PCB layout that is currently under review and improvement prior to sending out for raw boards.
See the hw/telemetrum tree in our public git repository for the current state of the gEDA design files.
We hope to be turning on boards and writing firmware over the Christmas / New Years holiday season. Stay tuned!