EEVblog Electronics Community Forum

General => General Technical Chat => Topic started by: BrianHG on March 25, 2018, 11:17:01 am

Title: Rubik's Cube solve in ms.
Post by: BrianHG on March 25, 2018, 11:17:01 am
0.38 Second Rubik's Cube Solve.  Some people have nothing better to do.....
Yet, it is still really impressive.  Enjoy!  :popcorn:
I think we have approached the physical speed limits of a Rubik's Cube.
https://www.youtube.com/watch?v=nt00QzKuNVY (https://www.youtube.com/watch?v=nt00QzKuNVY)
Title: Re: Rubik's Cube solve in ms.
Post by: NivagSwerdna on March 25, 2018, 12:07:45 pm
This uses a modified cube, machined to insert the rotors.  Not legitimate IMHO.
Title: Re: Rubik's Cube solve in ms.
Post by: BrianHG on March 25, 2018, 12:18:28 pm
All the high speed Rubik's Cube solvers I have seen use modified centers to hold them.
Though slow, this one deserves special mention.  The machinery is internal and not seen.
https://www.youtube.com/watch?v=qt_YYSK889k (https://www.youtube.com/watch?v=qt_YYSK889k)
Title: Re: Rubik's Cube solve in ms.
Post by: Tomorokoshi on March 25, 2018, 03:05:32 pm
LEGO solver:
https://youtu.be/staapsj3eRQ
Title: Re: Rubik's Cube solve in ms.
Post by: buck converter on March 25, 2018, 03:30:28 pm
nah dude check out Cubestormer III!!! :-DD
https://www.youtube.com/watch?v=X0pFZG7j5cE (https://www.youtube.com/watch?v=X0pFZG7j5cE)
Title: Re: Rubik's Cube solve in ms.
Post by: ebastler on March 25, 2018, 04:23:55 pm
Though slow, this one deserves special mention.  The machinery is internal and not seen.

It obviously "observes" the scrambling moves to know the state of the cube. I am not sure whether I like the fact that it then uses a different algorithm to solve it (which is just based on the final state, ignoring the history how the cube got scrambled, and taking many more moves).

On one hand, that makes it a "clean" cube solving algorithm. On the other hand, if you build specialized mechanics and an "automated cube" anyway, why not make use of the knowledge you have? If the scrambling sequence was shorter than XX moves, simply unscramble by reversing that sequence, because you know it's faster than what your algorithm could achieve otherwise?

Anyway, it's a neat effect. The mechanics are straightforward in principle, I would assume: 6 stationary motors attached to the center, each rotating one surface center element; the cube mechanism does the rest. But fitting the motors, battery and controller in there is a nice feat, even for this large cube.
Title: Re: Rubik's Cube solve in ms.
Post by: BrianHG on March 25, 2018, 05:25:06 pm
Though slow, this one deserves special mention.  The machinery is internal and not seen.

It obviously "observes" the scrambling moves to know the state of the cube. I am not sure whether I like the fact that it then uses a different algorithm to solve it (which is just based on the final state, ignoring the history how the cube got scrambled, and taking many more moves).

On one hand, that makes it a "clean" cube solving algorithm. On the other hand, if you build specialized mechanics and an "automated cube" anyway, why not make use of the knowledge you have? If the scrambling sequence was shorter than XX moves, simply unscramble by reversing that sequence, because you know it's faster than what your algorithm could achieve otherwise?

Anyway, it's a neat effect. The mechanics are straightforward in principle, I would assume: 6 stationary motors attached to the center, each rotating one surface center element; the cube mechanism does the rest. But fitting the motors, battery and controller in there is a nice feat, even for this large cube.
If you watch the video, it solves the cube with many more turns that it was scrambled in.  Hence, it is a poor algorithm.  However, I still like the visual effect.  Only if it ran smoother and without such long pauses between moves.
Title: Re: Rubik's Cube solve in ms.
Post by: ebastler on March 25, 2018, 05:31:18 pm
If you watch the video, it solves the cube with many more turns that it was scrambled in. 

Yes, that's what I said.

Quote
Only if it ran smoother and without such long pauses between moves.

The pauses between moves would certainly disappear if the controller would just reverse the scrambling movements it has observed before - not much calculation needed for that. The lack of precision in the rotation angles, which causes the mechanism to nearly get stuck a few times, probably needs a hardware solution. (Position encoders or other reference?)
Title: Re: Rubik's Cube solve in ms.
Post by: ivaylo on March 26, 2018, 06:55:35 am
This uses a modified cube, machined to insert the rotors.  Not legitimate IMHO.
Yeah, one good cube. No problem IMO. Mine in the 80s sucked, the trick was to lubricate with Nivea hand cream, I remember...
Title: Re: Rubik's Cube solve in ms.
Post by: Mr. Scram on March 26, 2018, 07:50:28 am
This uses a modified cube, machined to insert the rotors.  Not legitimate IMHO.
People modify their cubes all the time. Why would this not be legitimate?