Self-Solving Rubik’s Cube

Rubik’s Cube has been around for what seems like forever now, and has spawned an entire subculture devoted to solving the puzzle with automation. Most Rubik robots put the cube in a specially designed cradle bristling with actuators and sensors, and while those rigs are impressive, they don’t come close to this robotic Rubik solver built into the cube itself.

Fair warning that [Human Controller] doesn’t provide much detail on this build other than pictures; even translating the Japanese web page doesn’t offer much more information. But there are pictures, plus the video below, which reveal the engineering masterpiece encased within the standard sized Rubik’s cube. The internal mechanism of the original cube had been replaced by a spherical assembly around which the cube’s faces rotate. The sphere, which appears to be 3D-printed, houses six motors and gear trains, along with a microcontroller board and what appear to be Hall sensor boards to detect the position of each face. Everything is wired up with magnet wire to keep bundles to a minimum size, and buried deep inside is a LiPo battery pack. A disassembly video offers further clues to this ingenious device’s inner workings.

Once the cube senses that it has been scrambled, it sets to work on the solution, walking all over the table in the process. It’s clearly not just recording the scrambling steps and playing them back in reverse; the video below shows far more moves to solve the cube than the 15 it took to scramble it.

While we’re always impressed by marvels of speed like this robot with a 637 millisecond solve time, putting everything needed to solve the cube inside it is a feat worth celebrating. Here’s hoping that a build log shows up soon to satisfy our need for details.

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Rubik’s Robot So Fast It Looks Like a Glitch in the Matrix

From Ferraris to F-16s, some things just look fast. This Rubik’s Cube solving robot not only looks fast, it is fast: it solved a standard cube in 380 milliseconds. Blink during the video below and you’ll miss it — even on the high-speed we had trouble keeping track of the number of moves this solution took. It looked like about 20.

Beating the previous robot record of 637 milliseconds is just the icing on the cake of a very cool build undertaken by [Ben Katz]. He and his collaborator [Jared] put together a robot with a decidedly industrial look — aluminum extrusion chassis, six pancake servo motors with high-precision optical encoders, and polycarbonate panels for explosion containment which proved handy during development. The motors had to be modified to allow the encoders to be attached to the rear, and custom motor controllers were fabricated. [Jared] came up with a unique board to synchronize the six motors and prevent collisions between faces. Machine vision is provided by just two PlayStation Eye cameras; mounted at opposite corners of the enclosure, each camera can see three faces at a time. They had a little trouble distinguishing the red from the orange, which was solved with a Sharpie.

[Ben] and [Jared] think they can shave a few milliseconds here and there with tweaks, but even as it is, this is a great lesson in optimization and integration. We’ve covered Rubik’s robots before, like this two-motor slow and steady design and this six-motor build that solves a cube in less than a second.

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