Show HN: Mechanical Computer Kit (Roons)

48•uncial•2h ago

I built a mechanical computer kit: https://whomtech.com/show-hn

tl;dr: it's a cellular automaton on a "loom" of alternating bars, using contoured tiles to guide marbles through logic gates.

It's not just "Turing complete, job done"; I've tried to make it actually practical. Devices are compact, e.g. you can fit a binary adder into a 3cm square. It took me nearly two years and dozens of different approaches.

There's a sequence of interactive tutorials to try out, demo videos, and a janky simulator. I've also sent out a few prototype kits and have some more ready to go.

Please ask me anything, I will talk about this for hours.

-- Jesse

Comments

proaralyst•1h ago

This is cool! The simulator was useful for understanding what was going on, I hadn't realised until I watched a few that the roons can push marbles out in between squares.

uncial•1h ago

Thanks! Glad to hear the simulator was worthwhile, took me ages to hack it into shape. I did actually experiment with adding markings on the edges of the path roons, so that when you put them together, the "phantom channel" becomes visible. Ended up looking pretty cluttered though so I scrapped it.

shafoshaf•1h ago

All with a reference to the Rockwell Turbo Encabulator! Awesome.

uncial•1h ago

I'm grateful to Rockwell for their excellent research, but I think they really dropped the ball on side fumbling -- any competitive encabulator in 2025 really needs to be using bifurcated resonance.

sriram_malhar•1h ago

Good God! This is marvelous!

Johnbot•1h ago

This is really neat.

Is there any use for something like a hopper that dispenses new marbles continuously?

uncial•1h ago

Absolutely yes! I prototyped a hopper peripheral that doubled as marble storage. It hooked into the gear grid and used the rotation to drive a helical lift to carry the marbles up to the surface, where they'd enter the edge of an adjacent disk. I ended up setting it aside for 2 reasons: 1) Lack of time -- sad to say but I had to focus on getting the roons core ready. Too much to do! 2) The HDD peripheral -- this is a WIP that compactly stores and emits bitstreams. The way it's designed, it can be set to "reservoir" mode, which emits the continuous marble bitstream like you suggest. I figured it'd be redundant to have both a hopper and HDD, so I scrapped the hopper for now.

convolvatron•1h ago

you implied that there were scaling problems. it would be really fun and indstructive if one could use enough nodes to bulid a simple store and von neuman machine with instruction decode. but this seems like it would take a 10x10 array of your panels. do you think you can push this architecture that far?

uncial•1h ago

Yes, fantastic question! 10x10 is actually way more than we need -- don't know the minimum but I suspect 2x2 is possible. The interactive tutorials sketch out an approach to this. My instinct is to use SAM with timers for memory/program, then there's a couple of approaches in the tutorial for the instruction processor. Toying with the idea of an OISC to minimise space requirements. Tho we can always add a motor to the encabulator if we need to drive a larger grid!

uticus•1h ago

> ...the gears have a layer of phase baffles (I don’t know the technical term). These physically block the gears from connecting until they’re perfectly synced up...

perhaps the correct term is "key" [0]? only thing i could find to contribute to this masterful project, by pointing out unimportant details like this.

[0] https://en.wikipedia.org/wiki/Key_(engineering)

uncial•49m ago

That sounds like the right general category, but maybe not specific enough? We could call it an Uticus Key and see if we can get the name to stick, that might be funny. (Thanks for the kind words!)

uticus•58m ago

btw love the about page

> Do you want to work with a company servicing 6,000 Clients across 8 Different Countries, with turnover of more than 125 Million USD?...Are you looking for a Proven Track Record delivered by an Award-Winning Multinational Conglomerate with over Two Hundred Years of Business Experience?...If not, whomtech has you covered.

BlimpSpike•24m ago

How loud is it? Would it disrupt the whole office if I had it on my desk and occasionally played with it?

Very cool, I'll check back for the Kickstarter!

uncial•7m ago

With the FDM-printed prototype version there's a noticeable "a mechanism is occuring" sound, largely due to layer lines. Tbh it's not too loud rn but I'm confident we can get it smooth and whisper-quiet using any vaguely sane manufacturing technique (defaulting to injection moulded ABS but we have some options). The marbles/roons themselves are silent, it's just a question of getting the barrel cams to play nice.

cuken•21m ago

This is really really cool! The physicality of it is special and can be a huge help with some people to gain an understanding of whats actually happening on the micro scale. Reminds me very much of "Spintronics", a game that holds a special place in my heart as I could teach a traditionally conceptual topic to my kids.

Are the designs you've come up with 3D printed? I feel like there's a huge possibility of community advancement into this ecosystem (fully appreciating you should make a return on all of your time and creativity).

Thanks again for sharing something so cool.

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Show HN: Mechanical Computer Kit (Roons)

Comments

Government hackers are leading the use of attributed zero-days, Google says

Gaming news site Polygon gutted by layoffs amid sale to Valnet

Boost Your Shopify Store with Social Media Feeds

Idea Inoculation and Inferential Distance

An AI Agent for Launching and Optimizing Google Ads

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The Design Evolution of Mailboxes

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Achieving Human Level Competitive Robot Table Tennis

Want AI-Driven Productivity? Redesign Work

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SenseCam from Microsoft Research

Can You Blame the Chatbots?

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