Join 3,553 readers in helping fund MetaFilter (Hide)


Lego beats Man
November 30, 2011 10:45 AM   Subscribe

CubeStormer II solves the Rubik's Cube puzzle faster than the human world record.

From the video description:

This ARM Powered robot was designed, built and programmed by Mike Dobson and David Gilday, creators respectively of CubeStormer and Android Speedcuber.

The mechanics are constructed entirely from LEGO, including four MINDSTORMS NXT kits, with the addition of a Samsung Galaxy S II smartphone running a custom Android app as the robot's brain. Both the MINDSTORMS NXT kits and the Samsung Galaxy SII use a variety of ARM --based processors.

The app uses the phone's camera to capture images of each face of the Rubik's Cube which it processes to determine the scrambled colours. The solution is found using an advanced two-phase algorithm, originally developed for Speedcuber, enhanced to be multi-threaded to make effective use of the smartphone's dual-core ARM Cortex-A9 1.2GHz processor. The software finds an efficient solution to the puzzle which is optimised specifically for the capabilities of the four-grip mechanism. The app communicates via Bluetooth with software running on the ARM microprocessors in the LEGO NXT Intelligent Bricks which controls the motors driving the robot. During the physical solve, the app uses OpenGL ES on the phone's ARM Mali-400 MP GPU to display a graphical version of the cube being solved in real time.

Human speedcubers' solve times only include the physical manipulation of the cube and don't include some time which is allowed to "inspect" the cube beforehand. Times recorded by CubeStormer II are for the total solve including: image capture, software solution calculation and physical solve.
posted by Burhanistan (30 comments total) 8 users marked this as a favorite

 
For once the YouTube comments offered a profound and urgent question:

What happens if you put a hamster in there?
posted by yoink at 10:51 AM on November 30, 2011 [7 favorites]


David Gilday also did a neat one that is quite fast (not as fast as this one!) and can be built with a single Mindstorms set.

These are neat to see because in the past, when I followed a link to a Rubik's Cube solver, they were always very very slow--so on the one hand you're thinking, "That is pretty cool" and on the other hand you can't sit still to watch it.
posted by not that girl at 11:02 AM on November 30, 2011 [1 favorite]


This has kind of got me wondering how you set a world record for solving a Rubik's Cube. Obviously given any number of random permutations, some will be easier and quicker to solve than others. But just as obviously, you can't be handed a cube that only needs one twist to be finished and call yourself the world record holder with a time of 0:00.08.

Is it averaged over several solves? The Youtube comments say that the record is 5.27 for a "WCA scrambled cube". Does the WCA have a scrambling algorithm intended to make every starting point equally difficult? Is such a thing even possible?

Obviously given that its times include the scanning phase, this machine is so much faster than humans that it's probably not even a consideration (and it appears to beat the hell out of the cubes when solving them, which I find surprisingly endearing). But I'm curious now.
posted by penduluum at 11:03 AM on November 30, 2011 [1 favorite]


This ARM Powered robot
use a variety of ARM --based processors
the smartphone's dual-core ARM Cortex-A9 1.2GHz processor
running on the ARM microprocessors
on the phone's ARM Mali-400 MP GPU


Subtle.
posted by CaseyB at 11:06 AM on November 30, 2011 [1 favorite]


Unitasker.
posted by crunchland at 11:07 AM on November 30, 2011


Siri can't solve my Rubik's cube.
posted by acheekymonkey at 11:09 AM on November 30, 2011


> Siri can't solve my Rubik's cube.

Just out of curiosity, maybe someone with a new iPhone can ask Siri "what machine can solve a rubik's cube the fastest?"
posted by Burhanistan at 11:12 AM on November 30, 2011


Not fair, it has four hands!
posted by erinfern at 11:13 AM on November 30, 2011


Oh, I saw this already. He just started with a solved cube and filmed it in reverse. It's impressive he can turn it that well with his feet, though.
posted by Horace Rumpole at 11:15 AM on November 30, 2011 [5 favorites]


One of my classmates in an undergrad computer graphics course made an OpenGL demo that appeared to solve a Rubik's cube really rapidly. It worked basically via the Gondry method: starting with a solved cube it would scramble it one step at a time, recording each move. Then it would simply animate the process of stepping back move by move in reverse order until it returned to its starting point.
posted by contraption at 11:42 AM on November 30, 2011


Not fair, it has four hands!

Five. The other one holds the cube.
posted by rhizome at 11:52 AM on November 30, 2011


Just out of curiosity, maybe someone with a new iPhone can ask Siri "what machine can solve a rubik's cube the fastest?"

"Sugar Daddy, I can't search the web while your phone is locked." Yes, Siri calls me Sugar Daddy.
posted by hellphish at 12:05 PM on November 30, 2011


I love this. Two favorite toys from childhood (I know Mindstorms is a computer, but it's still Legos), one of which can look at the other and figure out how to solve it. I get the general gist of how it works, but it's still amazing.

I'm hoping he releases instructions (and code) for the Mindstorms-only version so my son and I can build one.
posted by bondcliff at 12:17 PM on November 30, 2011


Does the WCA have a scrambling algorithm intended to make every starting point equally difficult?

It sounds like they use a computer program to generate a random cube and a list of moves to get there, then someone manipulates it manually. I was wondering if that would really have random difficulty, but for a million random cubes, the distribution of minimum moves to solve were:

13 moves: 4
14 moves: 18
15 moves: 81
16 moves: 609
17 moves: 3893
18 moves: 23411
19 moves: 141366
20 moves: 830618

So a randomly drawn cube does have very good odds of being sufficiently hard to solve (99.9% will require 17 or more moves.)
posted by smackfu at 12:30 PM on November 30, 2011


Oops, that isn't minimum moves, just moves using a particular algorithm. Just go look at this page.
posted by smackfu at 12:34 PM on November 30, 2011 [1 favorite]


Try it again with a few odd-color stickers on there!
PROCESSING ERROR - PLEASE REPLACE CUBE.
posted by Metro Gnome at 12:35 PM on November 30, 2011 [1 favorite]


Rubik's Cube, robots, Smartphones, and Lego? THIS IS THE PERFECT POST.
posted by Mister_A at 12:53 PM on November 30, 2011 [1 favorite]


1. Awesome!
2. Why?
posted by slogger at 1:37 PM on November 30, 2011


GOTO 1
posted by Burhanistan at 1:39 PM on November 30, 2011 [2 favorites]


> This has kind of got me wondering how you set a world record for solving a Rubik's Cube.

At a typical WCA competition, you'd get both a single and an average result (for each category you participate in). You'd do some number of solves that day, maybe 5. The best time and worst time are dropped, and your average is the mean of the rest. The single is indeed your best of the 5. There are separate rankings for the two results.

The scrambles are indeed computer generated; there's no guarantee that each scramble will be equally "difficult", but that already is hard to measure, as it'll depend on which method you use and where on the cube you begin. Some of the most popular methods (Fridrich, Petrus, Roux) begin in completely different ways. Sometimes you might get lucky with a scramble that works well with your method. But that'll depend on you recognizing that you should start with this method, this corner, etc, and it could just as easily happen to someone else.
posted by segfault at 1:43 PM on November 30, 2011 [2 favorites]


To a man with a hammer, every Rubik's cube looks like a nail.
posted by chavenet at 2:11 PM on November 30, 2011


Rubik's Cube, robots, Smartphones, and Lego? THIS IS THE PERFECT POST.

Not until it mentions Arrested Development, Firefly, or Obama.

Oh wait!
posted by grubi at 2:36 PM on November 30, 2011


I had assumed, and hoped, that CubeStormer II was someone’s name.
posted by bongo_x at 6:01 PM on November 30, 2011


What happens if you put a hamster in there?

It will solve the hamster in under three seconds.
posted by qxntpqbbbqxl at 9:09 PM on November 30, 2011 [1 favorite]


1. Why?
2. Awesome!
posted by Bokononist at 12:32 AM on December 1, 2011


3 Mindstorms. And there you find why I lost interest in Mindstorms. So few inputs and outputs, you can string 3 together (PLUS! another computer!) to do a task like this. I just felt very strongly the ins and outs were artificially limited (nothing binary about the numbers) to sell more Mindstorms. Too many things I conceived of building that needed more of either, or even both.
posted by Goofyy at 1:33 AM on December 1, 2011


I wonder how fast you could get it working with proper hardware... A bunch of stepper motors could probably manipulate the cube incredibly fast, and you only need to image the sides once at the start.
posted by smackfu at 8:32 AM on December 1, 2011


I bet you would start to need a cube with higher engineering tolerances.
posted by rhizome at 5:18 PM on December 1, 2011


I was thinking the cube would probably explode.
posted by smackfu at 5:26 AM on December 2, 2011


Interestingly, solving a hamster is a one-way operation; once you've finished all sides will be solid red and it will remain solved thereafter, no matter how many times you twist it.
posted by contraption at 3:20 PM on December 2, 2011


« Older ThinkUp is a free, open source PHP/MySQL app that ...  |  The Netanyahu government has p... Newer »


This thread has been archived and is closed to new comments