Rubick’s Cube Solving Lego Mindstorms Robot

Posted on January 10, 2008  Comments (1)

Lego Mindstorms have really really provided some great tools for home robot engineering. JP Brown has several examples on his web site including this CubeSolver:

The longest part of the this project involved writing the color-recognition software. I downloaded the Logitech Quick Cam SDK from the Logitech Developer’s site (the LEGO Vision Cam is a repackaged Logitech Quick Cam) and used VB5 to write a fairly decent program (click the Code link for source). The color recognition is fairly robust (about one error every two cubes when well-calibrated), but not perfect, so I incorporated a feature that requires you to confirm that each face has been correctly scanned (and, optionally, allows you to correct the input manually) before it scans the next face.

My early attempts at building a cube solver were all stymied by grips that slipped. The worm-56t gave enough torque to turn, but the fingers couldn’t hang on and the grip was simply pried apart as the grabber rotated around the stationary cube face. I thought about changing the device’s name to ButterFingers.

I rebuilt the left and right grabbers six times (and the bottom grabber four times) trying elastic bands, Technic shocks, and pneumatics, before I came up with an adequate grip mechanism. In the present version, an axle runs from a motor through the center of the large Technic turntable to a worm screw. The worm screw turns two 24t gears mounted either side of the worm inside the body of the grabber.

Other home engineering favorites: Awesome Cat CamWindmill for ElectricityLego Autopilot First Flight

One Response to “Rubick’s Cube Solving Lego Mindstorms Robot”

  1. Curious Cat Science and Engineering Blog » Babbage Difference Engine In Lego
    March 31st, 2008 @ 5:47 pm

    […] Rubick”™s Cube Solving Lego Mindstorms Robot – Lego Autopilot Project Update – Open Source for LEGO Mindstorms – Donald Knuth, Computer […]

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