I gutted a the radio components from a cheap RC boat I got off Amazon and ordered a GPS shield and compass/accelerometer from Adafruit, thinking this would be a quick and easy project. Now I see why the other autonomous projects use the prebuilt ardupilot module! But it was fun and a great learning experience. As with most projects, I was highly motivated at first and got the software to convert lat/lon pairs into compass angles and so forth, but eventually I hit that stopping point and the project layed dormant for months in my closet. I woke up a few saturdays ago, particularly frustraited with my table full of unfinished projects, and said, "To hell with it, I'm going to finish the boat." The day was filled with a horrible blend of awful code, messy solder, and strands of electrical tape. That afternoon, I went out to a local lake with my wife and put the boat in the water. I didn't even care if it came back, so long as the project had some kind of closure. The damned thing went out exactly where it was supposed to, turned around and came back. I was shocked. That piece of junk actually worked! Now that I was once again excited, I brought it home and altered the code to crank it up to full speed, which led to a whole series of problems. After about four rescue swims over a two week period, the boat finally returned on its own. Its not pretty and the code isn't pretty. In fact, it doesn't even use radians, degrees, or meters. All of the units of measure are completely made up, but they are simple and effective so I didn't bother converting. All the navigational code is home-made so I consider myself lucky the thing ever turned on.
Mounted GoPro footage http://www.youtube.com/watch?v=yVGbIEKrOJM
The first complete run (At full speed)