Very often I end up with a big pile of Lego on the floor after constructing something. Cleaning up takes a lot of effort so I made up this bot to clean up most of the mess for me. The entire project is made up of two modules.
The first module is the collector. I built it using my NXT set. Two NXT motors lift a scoop made out of paper pasted to a Lego frame, tipping its contents into a cardboard box behind. The NXT is placed in the cardboard box. I originally wanted it to be placed somewhere else, but the wires weren't long enough. The third NXT motor drives a telescopic linear actuator, which turns a PF battery module on or off. Once on, the battery module powers 2 PF M-Motors, which will push a bowling-style arm which pushes anything below the scoop away. This serves to clear the area before the scoop lands after tipping its contents out.
I programmed the NXT such that the scoop will tip its contents out every 9 seconds. At the same time, the arm will be activated. The timing is adjusted such that the arm will activate and retract when the scoop is raised to avoid collisions.
The second module is the tank, or rather, the bulldozer. The chassis I used was my old tank built in Project Delta. I added another battery pack and PF M-motor to power the blade. It is controlled using PF IR control unit, so I could sit on the sofa and let the bulldozer do all the work.
It would have been better if everything is automated, rather than remote controlled, but I didn't have a second NXT set. Nevertheless, this RC bulldozer coupled with the automated collector works quite well at clearing most of my Lego pieces.
Watch the video here: http://www.youtube.com/watch?v=SI9gHucycBE