This is interesting, an open source software/hareware autopilot project… –
Paparazzi is a free and open-source hardware and software project intended to create an exceptionally powerful and versatile autopilot system by allowing and encouraging input from the community. The project includes not only the airborne hardware and software, from voltage regulators and GPS receivers to Kalman filtering code, but also a powerful and ever-expanding array of ground hardware and software including modems, antennas, and a highly evolved user-friendly ground control software interface.
All hardware and software is open-source and freely available to anyone under the GNU licencing agreement. Efforts are currently underway to organize production and retail sales of the autopilot and popular accessories, making the system much easier and more affordable for all.
The key feature of the paparazzi autopilot is its unique combination of infrared thermopiles and inertial measurement for attitude sensing, providing a robust and accurate attitude estimate that requires no ground calibration and can recover from any launch attitude.
Main Page – Paparazzi – Link.