Ground/collision proximity device

[macboffin]

Horizon Hobby are marketing a "beginners" RTF model, the Phantom Firebird,(comes complete with motor etc and Vee tail pitch and yaw control. Adverts show a sensor mounted in the wing support pylon over the "cabin" which is apparently a "ATC" ie anti crash technology device, automatically pulls the plane out of a steep dive and cut the motor to save a potential crash.
Sounds ripe for hacking for a variety of uses!

[404error]

The way the ACT works is it uses two optical sensors, one pointed at the sky and one at the ground. The sensors can tell when they are pointed at either the sky or the ground. When the top sensor 'sees' ground or the bottom sensor 'sees' sky (or both), the system takes over control and reduces throttle while feeding a little up elevator untill recovery. The dihedral wing keeps the plane nice and level with respect to the aleron direction. This system is not a ground sensor or a colision detection device. It works quite crudely but I am sure it is effective enough that most people would like it on their rudder/elevator-only planes. There was a UAV project done by some students that used a laser range finder (or two) to detect obstacles. Here is a link to a video released by the students.
http://www.youtube.com/watch?v=tfLwbW-R3IE
As for altitude detection, using an altimiter with a gps map (with the height of the ground about sea level) is the only method I can think of right now that wouldn't have issues caused by the attitude of the aircraft and still be reliable enough to .

An anti-colision device sophisticated enough to 'sense' objects and the ground would be a very complicated programming feat. These problems can be avoided by flying at a sensible altitude and setting a path that is well away from any buildings or anything that may be in the way of your flight path. Using google earth and scouting out your proposed flight path are things I do before setting up a flight path for my UAV.

[Unterhausen]

the FMA Copilot and devices like it work a lot better. The only time I tried to use the ACT on a plane I owned, I had to ditch the plane. ACT is a poor imitation of the Copilot in my opinion. But they don't do ground avoidance.