Does anyone have any contact with Bart? I have PM’d him a couple of times reference the prizes for the contest and haven't heard from him or received anything as of yet.
Thanks everybody for the votes. I was kind of expecting more people to submit their project at the last minute so no one could see their idea. I am kind of glad no one did, would have made more competition for me :) My daughter wanted to enter but we didn't have enough time to put together...
This site has a lot of information on sonar and optical sensors for the Pixhawk.
http://ardupilot.org/copter/docs/sonar.html
I don't believe anybody has interfaced the Arduino Ultrasonic with it.