I thought this was a funny thing that the Mythbusters did. I'm not saying that the contraption in the original video isn't real. The sad thing is that I think it is real and some complete geek with nothing better to do with his time made that device to solve the cube.
In blackest night, in shining day, My Will is all - I'll have my way! With Emerald Light in focused ray, This Duck will rule! (If that's okay?)
I'm inclined to call foul for other reasons. While I have no grounds for doubting that the machine works as advertised, for the purposes of the video, I think it was staged. Seven moves is a suspiciously efficient solution for a general Rubiks cube solving algorithm. Either the machine knew exactly what it was getting, or it had already calalogued all 200 million permutations possible from seven moves, indexed by cubelet position.
Hmm, now I think of it, there's absolutely no reason why the machine can't scan this supposed catalogue for a quickie solution before embarking on an inefficient general solution. Nevermind.
Good intentions are no substitute for a good education.
I take my fun very seriously.
I think it was staged.
Of course it was staged for the purpose of the video. If it would solve a random position, it would need a half-hour video. 2 minutes of it is interesting, more is not needed to show off the principles.
It is actually quite easy to do this
There are already programs that very quickly provide a solution for any configuration of the Cube. Such a program is running on the PC. The only two things you need now are: (1) A way to transfer the Cube's initial configuration to the program, and (2) a way to translate the solution to moves of the contraption.
(1) is done with the camera mounted above the contraption -- this is, in fact, the hardest to accomplish and it is not done by any Lego-stuff. Lego Mindstorms cannot process more than four separate input values, and thus cannot process camera images. This is all done on the PC.
(2) is the interesting Lego-bit, but it is fairly easy to accomplish. The solution for the Cube is a list of moves, which are translated to tipping of the Cube, rotating the base, and rotating the base while holding the top. It will probably take a few days to get it all working well, but nothing above and beyond amateur Mindstorms knowledge is needed.
Though I have to admit that I think that this is all extremely cool.