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  • This looks like a good place to ask HN:

    I've started with a solved cube, then turned 2 sides sharing an edge, alternatively (same direction) expecting the cube to get messed up but then returning to its solved state.

    It never got solved! Maybe i didn't do it enough (i did it hundreds of times i think). Has anyone got an explanation?

    by cellular
  • It takes something like 60 turns or so in my experience. you probably messed up while doing it.
    by avandekleut
  • It should take 105 repetitions:

    https://alpha.twizzle.net/explore/?alg=%28U+R%29105

    Unless by "same direction" you mean "opposite direction", in which case 63 works:

    https://alpha.twizzle.net/explore/?alg=%28U+R%27%2963

    by rokicki
  • The cyclic group generated by e.g. RU has order 105 (so 210 total turns or 105 of each side, alternated). If you have some math know-how, check out [1]. If you don't, take my word for it: when I was a teenager playing around with cubes, I once had a similar experience trying to do the same thing you did - when I went relatively quickly it never returned to the solved state, but when I was very deliberate about each turn, I got the 105 result (not by counting back then, but by rough time estimate given the figure I just looked up). Both you and I probably accidentally threw in one or more double-turns (like a U2) in there, or undercounted and gave up well before the cycle had completed (I, too, had thought I'd made "hundreds" of moves).

    [1] https://faculty.etsu.edu/gardnerr/4127/algebra-club/rubik-ta... - slide 41

    by JonathanMerklin
  • The personality of creator really shines through in the software. Douglas Adams would be pleased, I hope loads of hackers will be inspired to make more 'Adamsian' robots.
    by aEJ04Izw5HYm
  • I'm looking forward to more genuine people personalities from Unsirious Cybernetics.
    by moffkalast
  • Solving a cube has two parts, determining the moves and making the moves. For humans these two activities happen mostly in parallel. For robots, moves were already determined before the start. So the time taken is merely all about speed of move making.
    by zkmon
  • This is a hot contender for the Most Awesome Thing I Saw On The Internet In 2025. Incredible work!
    by shmeeed
  • Cool!!, I've created this one 16 years ago: https://www.youtube.com/watch?v=bkWLQZgi9uE

    I can see very similar movements this robot is doing compared to my old robot. I really like the screen outputs of it.

    by klaudioz
  • SARCASM: the only acronym worth building hardware for
    by teunlao
  • I think you built a rubik cube solving machine just to show-case your acronym ;-) Super cool work.
    by xiaoyu2006
  • There's a lot more detail describing the project in a couple of forum posts here: https://forum.pjrc.com/index.php?threads/sarcasm-an-over-eng...
    by chris_overseas
  • I want an automatic scrambling machine, not an automatic solving machine. Two cubes. While you're solving one, the other one is being scrambled. Cubers spend way more time scrambling than solving. Scrambling is the annoying part that needs automating.
    by noman-land
  • Can’t you just run the solving machine in reverse?
    by dullcrisp
  • At least until a certain level, scrambling (according to a given "algorithm") is a good way to practice moves. It shouldn't take much longer than a solution either, you are not solving the cube in under 30 moves. And if you don't care about the scramble it's even faster. So I don't think the "way more time" is entirely accurate. It may feel like it though.
    by rplnt
  • I’m completely not in this space but your comment had me wondering: are there digital cube faces? That is, a real physical cube but with faces that can instantly be set to a given color?
    by LVB
  • This is in my mind the hardest part as well.

    I can solve the cube with the regular “easy” 3-layer approach, but I’d like to solve it faster.

    The issue is that the techniques for fast solving require to learn many different patterns to get to the right solution fast.

    I don’t know really how ppl that solve it fast accomplish getting to that level, but to me it would be amazing if i could just set the cube in know scrambled states that let me practice and memorize specific algorithms repeatedly until I learn them.

    The problem is that I don’t know enough yet to distinguish which are those initial states, let alone setting the cube in that state, so something that could set it up for me to practice would be amazing

    by alejo
  • The aesthetics of this are great. Nice job.

    Demo: https://youtube.com/shorts/Xer4mPZZH8E

    by derac
  • This is absolutely the most charming thing I've seen in a hot minute.

    For anyone also thoroughly enchanted like me, there is an additional, longer demo:

    https://www.youtube.com/watch?v=WV52RtuWXk0

    Living in software land, I do wonder how hard is the undertaking to build one of my own.

    As a hobbyist cuber, this project reeks of icebreaking potential for the rest of the times I'm not actively solving -- leave it on my desk next to a cube... random coworker walks by, sees and grabs the cube, shuffles it, and chucks it into the SARCASM machine, enjoys a minute of novelty, ????, profit!

    by boneitis
  • Related - there's a Guinness record for the fastest Rubik's cube solving robot; it stands at 103 milliseconds:

    https://www.youtube.com/shorts/ue2gZ2vxs48

    https://engineering.purdue.edu/ECE/News/2025/purdue-ece-stud...

    by nneonneo
  • Robotic solver is more of a physical problem than a mental one. A photo of the cube from top and bottom corners and you can solve it in a nanosecond
    by hammock
  • Impressive and a bit mad.
    by hermitcrab
  • I wonder how many cubes they exploded in the making of that robot
    by adrianN
  • Hi all. I just found this thread. I'm the creator of SARCASM. Thanks to the OP for sharing. I spent many hours on this build but it was a lot of fun. I'm happy to see that others are enjoying it also :-)

    If you're interested in the technical side, I wrote detailed posts on the hardware and software on the Teensy forum: https://forum.pjrc.com/index.php?threads/sarcasm-an-over-eng...

    by vindar79
  • Can you post the STL files for the shell and Arms?

    Great project.

    by ewalk153
  • This makes me want to teleport it back to the 1920s, enclose it in glass and charge people a nickel to use it! You'd be rich!
    by ramses0
  • > I'm the creator of SARCASM.

    Glad I’m not the only one who sometimes justifies spending time on project purely because of the name I can give to them.

    by scrollaway
  • I love how you approached the problem and perfectioned the "product" in all aspects. There's so many playful details that could easily go unnoticed! You're impressively resourceful, and one can tell this was a work of love.

    I wish I could buy something like it as a DIY set, just to own it, admire it, show it to people, and have everybody be in awe of your work. What a time to be alive that stuff like this is in reach of a sufficiently dedicated hobbyist!

    by shmeeed
  • I think this is an amazing all around build combining the physical mechanics for solving (a relatively understood problem in rubik's robot solving scene) but along with the graphics integration and some real personality from the bot avatar that gave me quite a few laughs. Well done!
    by ugh123
  • Very cool. I remember being the first kid at school to have a Rubiks cube, in the 70s (I read about it in Omni magazine). I had no idea how to solve it. I sent off for a booklet about solving it. I got back a booklet about group theory, far beyond my teenage brain.
    by hermitcrab