S.A.R.C.A.S.M: Slightly Annoying Rubik's Cube Automatic Solving Machine
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Robotics
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The S.A.R.C.A.S.M. project is a humorous, over-engineered Rubik's Cube solving robot that has garnered significant attention and praise from the HN community for its creativity and technical complexity.
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Oct 31, 2025 at 7:03 PM EDT
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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!
https://www.youtube.com/shorts/ue2gZ2vxs48
https://engineering.purdue.edu/ECE/News/2025/purdue-ece-stud...
Second, nanosecond? You know that a GHz CPU does a single clock tick in one nanosecond, right?
It would be neat if it offered to scramble when you insert an already solved cube (demoed in the video), and maybe have options for the amount of randomness.
Is there an unbiased scrambling (or random generation) algorithm, or is it enough to just generate N random moves?
TL;DR fair scrambling is exactly as fast (same throughout) as solving random cubes! Neat.
[0] https://www.cubelelo.com/blogs/cubing/how-to-scramble-a-rubi...
[1] https://en.wikipedia.org/wiki/Optimal_solutions_for_the_Rubi...
https://m.youtube.com/watch?v=l-TWH5W-1fw
https://exmarscube.com/product/ex-mars-ai-robot-cube/
That being said, while looking up those links, I found out that, since I got out of the hobby, smart cubes have become a thing, and are made by real speedcube manufacturers.
https://www.gancube.com/products/gan-356-i-carry-smart-magic...
This is an easier problem to solve. I'm not sure if you have to solve it first or if it can identify pieces on power up, but after that it's just tracking rotations, which can be done from the (fixed position) centres alone. But if an actual speedcube manufacturer can already fit those electronics in without comprising performance, I can't imagine it's that much harder to fit some addressable LEDs on some slip-ring-esque connections. Must just not be much of a market.
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
Just like everything else in life, they do it really slow and with lots and lots and lots of errors at first, but (and this is where the magic happens) keep doing it, training hours a day or their entire week ends, for years.
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...
Great project.
Glad I’m not the only one who sometimes justifies spending time on project purely because of the name I can give to them.
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!
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?
https://alpha.twizzle.net/explore/?alg=%28U+R%29105
Unless by "same direction" you mean "opposite direction", in which case 63 works:
[1] https://faculty.etsu.edu/gardnerr/4127/algebra-club/rubik-ta... - slide 41
I can see very similar movements this robot is doing compared to my old robot. I really like the screen outputs of it.
You are missing the last full stop, unless your project is actually meant to be called "S.A.R.C.A.S. M"
An initialism either uses full stops after all letters or none of them.
Uses a rpi 2 w, works well, can solve and scramble 3x3x3 cubes, using just 2 servo motors.
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