Jason over at Haqckszine found the Tilted Twister, a LEGO NXT robot that can solve a Rubik’s Cube without the help of a PC. It’s really impressive to watch!
Just place the scrambled cube on Tilted Twister’s turntable. An ultrasonic sensor detects its presence and starts to read the colors of the cube faces using a light sensor. The robot turns and tilts the cube in order to read all the faces of the cube. It then calculates a solution and executes the moves by turning, tilting and twisting the cube.
Building instructions and source code are available on Hans Andersson’s site.