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  3. /S.A.R.C.A.S.M: Slightly Annoying Rubik's Cube Automatic Solving Machine
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  3. /S.A.R.C.A.S.M: Slightly Annoying Rubik's Cube Automatic Solving Machine
Oct 31, 2025 at 7:03 PM EDT

S.A.R.C.A.S.M: Slightly Annoying Rubik's Cube Automatic Solving Machine

chris_overseas
278 points
57 comments

Mood

excited

Sentiment

positive

Category

other

Key topics

Robotics

Artificial Intelligence

DIY Projects

Debate intensity20/100

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.

Snapshot generated from the HN discussion

Discussion Activity

Very active discussion

First comment

2h

Peak period

55

Day 1

Avg / period

19

Comment distribution57 data points
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Based on 57 loaded comments

Key moments

  1. 01Story posted

    Oct 31, 2025 at 7:03 PM EDT

    25 days ago

    Step 01
  2. 02First comment

    Oct 31, 2025 at 8:35 PM EDT

    2h after posting

    Step 02
  3. 03Peak activity

    55 comments in Day 1

    Hottest window of the conversation

    Step 03
  4. 04Latest activity

    Nov 3, 2025 at 4:51 PM EST

    22 days ago

    Step 04

Generating AI Summary...

Analyzing up to 500 comments to identify key contributors and discussion patterns

Discussion (57 comments)
Showing 57 comments
derac
25 days ago
1 reply
The aesthetics of this are great. Nice job.

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

boneitis
25 days ago
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!

stavros
25 days ago
1 reply
This is fantastic, how did it not get confused by the blue logo on the cube in the video?
trenchpilgrim
25 days ago
1 reply
Western cubes always have white opposite yellow. Japanese cubes always have white opposite blue. (The center piece on each side can be considered "fixed" relative to all moves.)
stavros
25 days ago
Ahh right, I forgot the center piece defines the face color, thanks.
nneonneo
25 days ago
3 replies
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...

hammock
25 days ago
1 reply
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
teiferer
24 days ago
2 replies
First, you still need to optimize the solution to fit the constraints of mechanical solving. It needs to be as few moves as possible, some of them are parallelizable, etc. Not a trivial problem.

Second, nanosecond? You know that a GHz CPU does a single clock tick in one nanosecond, right?

rossant
24 days ago
1 reply
Maybe there's a new instruction we don't know about in modern CPUs, like RUBIK_SOLVE or something.
SwiftyBug
24 days ago
1 reply
I mean, we've had RUN_DOOM for many years now, so why not?
amypetrik8
24 days ago
yes, in python either 1) "import doom" or 2) "from rubik import cube"
Tempest1981
24 days ago
They probably meant millisecond
hermitcrab
24 days ago
Impressive and a bit mad.
adrianN
24 days ago
I wonder how many cubes they exploded in the making of that robot
noman-land
25 days ago
4 replies
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.
dullcrisp
25 days ago
2 replies
Can’t you just run the solving machine in reverse?
noman-land
25 days ago
2 replies
You can but it doesn't need to be smart at all. It doesn't need cameras. It's a much simpler machine.
boneitis
25 days ago
Funny enough, that (e: the shuffle function mentioned in original thread post, just realized my awkward comment placement) sounds like a very reasonable stretch goal/feature add-on, although I'm not sure this particular machine could shuffle quickly enough for speedcuber types.
rplnt
24 days ago
It needs to be somewhat smart, if you want to track your scrambles and times. But yes, it doesn't need cameras if it trusts you.
schiffern
25 days ago
1 reply
Yeah, it's just a software change to the existing machine. If you generate a target scrambled state it's literally the solver algorithm in reverse too.

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?

schiffern
24 days ago
To answer my own question, competitive cubing uses unbiased randomization algorithms.[0] To minimize scrambling time, it could fairly generate a random configuration and then optimally scramble the cube in ~18 moves.[1]

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...

LVB
25 days ago
2 replies
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?
sunnybeetroot
25 days ago
This is a great question! Doesn’t seem like it’d be hard to make if it doesn’t already exist
apple1417
24 days ago
They exist, but one of the problems is they're not particularly good cubes. While it might help you learn the basics, not being able to handle it like a speedcube means they're probably not going to help you get faster.

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.

alejo
25 days ago
1 reply
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

0x264
24 days ago
> I don’t know really how ppl that solve it fast accomplish getting to that level

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.

rplnt
24 days ago
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.
vindar79
24 days ago
6 replies
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...

ewalk153
24 days ago
1 reply
Can you post the STL files for the shell and Arms?

Great project.

vindar79
24 days ago
1 reply
Sure. I will add them on github later today. The repo is currently in a very messy state. I would like to clean it and provide detailled assembly steps but I have to much work currently. Hopefully I can do this in a couple of months.
vindar79
24 days ago
Done. Added stl files to the repo.
scrollaway
24 days ago
1 reply
> 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.

vindar79
24 days ago
hehe, it was indeed a major motivation :-)
ramses0
24 days ago
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!
shmeeed
24 days ago
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!

ugh123
24 days ago
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!
hermitcrab
24 days ago
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.
aEJ04Izw5HYm
24 days ago
1 reply
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.
moffkalast
24 days ago
I'm looking forward to more genuine people personalities from Unsirious Cybernetics.
cellular
24 days ago
3 replies
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?

rokicki
24 days ago
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

avandekleut
22 days ago
It takes something like 60 turns or so in my experience. you probably messed up while doing it.
JonathanMerklin
24 days ago
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

watson
24 days ago
This is one of the best arguments for purchasing a 3D printer
klaudioz
24 days ago
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.

xiaoyu2006
25 days ago
I think you built a rubik cube solving machine just to show-case your acronym ;-) Super cool work.
metalman
24 days ago
whats the point? rubicubes are for hoomans got one when I was 12, solved the next day, couldn't tell you how,got better, got fast, got bored, never touched one again. but this much....not knowing and solving as an unconsious process is likely to be the advantage or to put it another way, knowing is limmiting and constrains doing. hooman thing.right
teunlao
25 days ago
SARCASM: the only acronym worth building hardware for
dugidugout
25 days ago
The screen ui aestetic and audio (specifically the dubbing) remind me of the silver case series, may be a total reach, nice touches none the less!

https://en.wikipedia.org/wiki/The_Silver_Case

chris_overseas
25 days ago
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...
optimiz3
25 days ago
Impressive work. Curious to how many hours of labor what the development path was. Several man-years possibly?
bolangi
24 days ago
So does that make the developer a sarcasmaholic?

https://www.youtube.com/watch?v=JcOfFeKXcd4

shmeeed
25 days ago
This is a hot contender for the Most Awesome Thing I Saw On The Internet In 2025. Incredible work!
wilg
25 days ago
It's a cool project, but also they're really underselling the amount of work put in to make it annoying.
branon
24 days ago
Pedantic pet peeve: it'd be S.A.R.C.A.S.M. or SARCASM but not S.A.R.C.A.S.M

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.

slug
24 days ago
I built a cubotino a few years ago, similar mechanism, see https://github.com/AndreaFavero71/cubotino

Uses a rpi 2 w, works well, can solve and scramble 3x3x3 cubes, using just 2 servo motors.

zkmon
24 days ago
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.
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ID: 45777682Type: storyLast synced: 11/20/2025, 5:36:19 PM

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