LEGO NXT Rubik's Cube solver (FINAL version)

This is our completed Rubik's cube solving robot. Here we see the entire process. First it scans the surface of the cube (so it knows the initial state) and then it solves it entirely by itself. I would like to emphasize that the robot solves the cube without help from a pc. Source code can be found here: http://www.daimi.au.dk/~jn/lego/esea-rubikssolver.zip

Category:

Education

Tags:

• Completed
• LEGO
• NXT
• Rubiks
• cube
• solver

[CH0RUS]

Video is backwards.

[atbrask]

Very funny, but no. There probably are a number of backwards videos "solving" cubes here on YouTube, but this isn't one of them. With this machine it would actually be quite hard to make it do it backwards and still look plausible. It can only flip the cube by ramming it from the right.

[dandil]

if jur only using 2 sensors, how does it read the middle row? also, there are ALOT of possible combinations, does the NXT have enough memory for all of them plus the solutions? also, whats the 3rd sensor then? very kool project tough, must have taken some time.

[atbrask]

During each pass it scans the upper and the middle row. By tilting, rotating and scanning each surface several times we get full coverage of the cube.

There are alot of combinations, yes. Therefore it doesn't make sense to hardcode all solutions in the NXT. It is solved algorithmically.

Our third sensor is the emergency stop button (the red thing to the left in the picture). The third wire to the gripping arm is to an extra light source. The color sensors are kinda picky.

[ManfredW]

that is why nobody should mess with denmark. what would you all do without lego?!!!1111

[gggooo09]

yes less take the fun out of actually solving the rubiks cube

[foong1995]

whaow!!!

[linklego84672]

nice but a little slow

[Chaosmakerrr]

Always fun when you have this kinda classes and you actually manage to blow up one of those sensors :p

Then you can talk about being screwed.

Any way gz your project.

[atbrask]

You're right about the algorithm. It generates a solution which it then follows.

I can't remember the exact CPU and memory limitations, but I'm sure Wikipedia can help you. It's a standard NXT with third part firmware.

Now to your questions regarding the scanning and the reasoning behind using only two sensors..

It was purely a matter of cost. Each color sensor can only measure a single color, or pixel, at a time. These sensors are (or at least were) quite expensive. So we could only get two.

[Sahuagin]

ok I see you mentioned that the sensor only sees two rows at a time. Is the LEGO NXT resources that limited that you can't use three sensors, or is that a limitation to make the project/assignment more interesting/challenging?

[Sahuagin]

does your algorithm generate a solution first, that the robot then follows, or is there an algorithm that determines the next move always dependant on the current state of the cube?

I suppose it is the first, since the machine scans the cube only once. What is the memory and CPU limitations of the robot?

Also, why does it scan so many times (17?)? shouldn't 6 scans be all it needs (or 3 if there is a sensor on the back too)?

[CPBlazier]

i got mine yesterday too! Have you considered programming with ROBOLAB yet? Or better, buy the old original 9794 RIS 1.0 Kit, Then use robolab. It will help you understand the basics, The move on to the NXT, and make sure you click every block you see and experiment with your robot. Good luck!

[ailenpangwin]

Wow that was amazing. one day i want to make something that cool. i just got my mindstorm for Christmas and i cant understand how to program it its soo confusing. i built it fine but programming is hard. im trying tri bot.

Got any tips cause im pretty stuck