LEGO MINDSTORMS EV3 solves Rubik’s Cubes in under two minutes

Update: Instructions are now available here!

Click the image for building and programming instructions.

David Gilday, designer of the NXT Mindcuber bonus model is back with an all new EV3 cube solving robot: Mindcub3r. Here’s what David says about his design, and be sure to check out the video of the robot in action below:

MindCub3r is a new LEGO® Rubik’s Cube® solver that can be built from a single LEGO® MINDSTORMS® EV3 set Item: 31313.

MindCub3r is more efficient than previous versions of MindCuber that were created with MINDSTORMS NXT. It is currently able to solve the Rubik’s Cube puzzle in an average of about 24 moves in 1 min 50 secs.

This efficiency is enabled by the higher performance ARM9 processor and significantly greater 64MB RAM in the EV3 than the previous NXT. A new software algorithm was developed especially for the robot with a four-phase lookup-table driven algorithm requiring approximately 5MB RAM.

David says that he’ll make building and programming instructions available later this year, so stay tuned!

62 Responses
    1. kris

      you can see it as you are on youtube and type lego ev3 cubeslover
      and than the same picture and the distiptoin…

      i hope this helps you.

    1. kris

      you can see it as you are on youtube and type lego ev3 cubeslover
      and than the same picture and the distiptoin…

      i hope this helps you.

    1. Jorge

      Yes, scanning is slower. with NXT was 25s, now is 40s.
      Perhaps is due to the medium motor instead of large motor for moving the color sensor.

    2. kris

      you can see it as you are on youtube and type lego ev3 cubeslover
      and than the same picture and the distiptoin…

      i hope this helps you.

    1. kris

      you can see it as you are on youtube and type lego ev3 cubeslover
      and than the same picture and the distiptoin…

      i hope this helps you.

  1. Harold Ka

    Hello,

    it is very fantastic and I would like to make the project.
    I have EV3 but i don’t know how to make the program.

    could you share the program for me?
    my kid is really like it.

    Thanks
    Harold Ka from south korea

  2. Ethan

    Thank you for your help finding the program. I was able to load it on the brick. Then to start with I pried the cube apart and squirted some WD-40 inside so it spins easily. It goes through the scanning process and starts solving the cube. After about 5-6 spins it gets stuck because the cube is not lined up straight. How do I fix this?

    1. Jan-Gerard van der Toorn

      The size of the cube matters a lot. When your cube is somewhat smaller than the one that was used by the developer of the Mindcub3r, your cube can turn a bit more within the table.
      That results in somewhat larger backlash of the cube, when the lowest ring it turned with respect to the rest of the cube. If there remains a misalignment of the rings, a turn of a perpendicular set of rings may result in a jam.
      You question is: how to solve it?
      You will have to modify the program slightly, and tune the backlash compensation value to match your particular cube. That is easy, since the creator of the Mindcub3r already anticipated on a backlash compensation mechanism.
      Open the program MindCub3r-v1p1.ev3, then open the Turn.3v3p subroutine and change the value of the numeric constant in the switch block in the upper center: [IMG]http://i58.tinypic.com/2ypcby0.png[/IMG]. In fact, you have to change both values, for both switch cases: the +65 and the -65. If your cube is smaller, you need to fill in a larger value.
      The transmission ratio formed by the gears between motor B and the table itself is 12/36. So to correct for 5 degrees misalignment of the lower ring of the cube, when turning, you need 36/12*5 degrees = 15 degrees extra rotation. Then, change the +65 into +80 and the minus -65 into -80.
      You may have to experiment a bit to get your cube solver working best.
      Note that the initial alignment of the cube (after you removed the cube, and before inserting it) is critical, and may be the cause of the problem if you experience jams after rotating in one direction, and not in the other. You can adjust the initial table alignment by pressing the left/right buttons on the brick when the robot is waiting for the cube to be inserted.
      Good luck.

      1. Ethan

        I already took it apart, but I will put it back together soon, And Ill try doing what you suggested. Thanks for the help!

    1. Ethan

      No offence but it did scan it, It even solved it because I put it in then it would get jammed, So I would pull it out and restart the program and so on until it was solved.

  3. phil eudy

    I downloaded your building instructions and EV3 program, both of them look awesome. I cant wait to build this this to show all my other Lego friends.
    Three questions:
    1. Would you mind if I take this cube solver to a Lego convention event to show it off and of course give you credit for the whole design?
    2. Are you using a standard Rubiks cube for this model?
    3. Are you planning on anytime in the future of building a machine like this to solve the 5x5x5 cube? Regards Phil

  4. Shane Abell

    What is the reason the mindcub3r does not work with the education kit? Is it just the build or is it the associated files/software??? Is it because there are different sensors??
    Cheers Shane

  5. Kamden Bolhuis

    did not work it said this
    Unable to compile some documents for deployment:
    ScanCube.ev3p: Use of a block which no longer exists.
    ScanPiece.ev3p: Use of a block which no longer exists.
    ScanFace.ev3p: Use of a block which no longer exists.
    ScanMiddle.ev3p: Use of a block which no longer exists.
    ScanEdge.ev3p: Use of a block which no longer exists.
    ScanCorner.ev3p: Use of a block which no longer exists.
    ScanRGB.ev3p: Use of a block which no longer exists.
    ScanAndSolve.ev3p: Use of a block which no longer exists.
    MindCub3r.ev3p: Use of a block which no longer exists.

      1. derp

        ok so on mindcuber.com if you scroll down a little bit and select the 31313 version he shows how to download this RGB color block which is imported to your programming thing where you open the first file that doesn’t work and then it works. (he tells it in more detail…)

  6. Ik heb de mindcub3r gedownload en als ik op start klik zegt de computer dat de robot het program niet kan afspelen omdat er bepaalde documenten voor impelentatie samengesteld kunnen woorden. Hoe kan ik dit oplossen

  7. dine elhanna merabet

    bonjour;
    quel est le problème s’il vous plait. j’ai téléchargé le programme sur votre site. merci

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