The Lego Great Ball Contraption | Hacker News Reader

The Lego Great Ball Contraption

kottke.org

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I participated in GBC at Brickworld Chicago in 2023! It was fun, but much more work than you'd expect. It's a full day's work keeping all the machines running, clearing jams, herding balls back into the chain when one mechanism goes out of wack. It was fun to meet the other folks there.

I should really get around to properly documenting my design, but here's a short video of the version I brought to Brickworld: https://youtu.be/wdP656HuY6M

I have a couple of sets from Fischer Technik and can't recommend them enough if watching marbles roll in an infinite cycle is your thing :)

https://www.fischertechnik.de/en/toys/marble-runs

Really well-made, excellent instructions and a very Lego-like experience.

Fischertechnik is a great engineering gateway drug for kids

If you've got a 3D printer and some Lego lying around, you can print Lego-compatible marble run parts, one example: https://hackaday.io/project/165034-marble-run-building-brick...

I love the addition of the infinite domino machine that has nothing to do with ball transport.

I wish the Lego Technix line would expand to be more about weird machines like this.

I asked my brother-in-law if my nephew would like a more advanced Technix set as a gift, he said no, they were mostly cars and vehicles and he wasn’t interested in that kind of thing. I wouldn’t have been at that age either. A wicked Rube Goldberg machine though…

There is a Turing Machine on Lego Ideas!

Oh wow, that’s tight. Gonna register tomorrow so I can boost this. https://ideas.lego.com/projects/10a3239f-4562-4d23-ba8e-f4fc...

Brilliant! Supported!

I think the Technic Lego kits that I grew up with (that were more about how things worked rather than looking exactly like the thing) have been rebranded as "Lego Education": https://education.lego.com/en-gb/shop/secondary/

They're pretty expensive, though!

Lego education used to be called "Lego Dacta". https://www.brothers-brick.com/2020/01/31/a-history-of-lego-...

https://www.fischertechnik.de/en/toys/robotics

My kids are mostly uninterested in the cars, but they loved the recent 42197 Earth and Moon orbiting the Sun.

They also like using the sorted boxes of Technic pieces to build crazy contraptions and my oldest has gotten into Spike Prime programming (Scratch/Blockly or Python).

Looks like some of the contraptions in the video made by Akiyuki are for sale at BuildaMOC: https://buildamoc.com/search?q=akiyuki&type=product

Searching for GBC yields a bunch of other kits: https://buildamoc.com/search?q=gbc&type=product

Feels like https://blueballfixed.ytmnd.com/ come to life

Similarly, the xkcd webcomic made an infinitely tileable, user-submitted version of this for his april fools comic this year: https://xkcd.com/2916/#xt=10&yt=78

There is always an XKCD for anything

I helped man one at a Brickworld. Lots of chasing down little plastic soccer balls all over the floor.

The whole thing just makes sense as a software dev. There's an input standard, output standard, and I guess a processing rate expectation (or not - that was probably the second biggest issue we faced was some slow contraptions that would back up). (The first biggest issue was a contraption that "pinged" the balls through the air to a landing container and would sometimes send them off randomly or kids would try to catch them.)

This is partly from LEGO fans previous work on railroad, town, space base, etc. modular builds where they have a spec for where each unit should connect and people bring in their own creations and link them all up.

I've always wanted to do something like the great ball contraption in general at makerfaires but open to all kinds of build materials, techniques, power, etc.

I think the spec is supposed to be one ball per second, but I guess that's not really adhered to.

Tangentially, I think it'd be interesting to use something like this to explain the networking concepts of throughout, latency, jitter, baud vs bits per second, symbol rate and bits per symbol.

You can find analogous examples in the main video to compare to all of those concepts.

I'd suggest looking through the videos on akiyuki's channel. It's a gold mine of novel Lego contraptions and isn't limited to GBCs, although it is majorly that.

It's truly a gem of a channel ! This clock was particularly mesmerizing : https://youtu.be/GUdlSYC1cCE

The railway system series is also great, you'll see the step by step construction of the system and later on its use in a GBC event.

The undisputed king of GBC. His modules are works of art. So many incredibly intricate and innovated mechanisms with lots of precisely coordinated parts, yet driven from a single standard Lego motor. And the videos are well-shot, clear and to the point.

Some favorites:

- Catch and spin robots: https://www.youtube.com/watch?v=lXF7mgZ9mzk

- Basketball shooter: https://www.youtube.com/watch?v=Yud9ukF5cV8

- Pole dancing quartet (SFW): https://www.youtube.com/watch?v=6s0a7Z70WxM

It is amazing how much is added by the eyeballs. Imagining it without would seem somehow lifeless in comparison.

This reminds me somewhat of Gravitrax which is a marble run system. One youtuber implemented a 19-bit adder with it: https://www.youtube.com/watch?v=TTK-vcwSm7s, a clock: https://www.youtube.com/watch?v=AOu0r1iUevk and other crazy creations. All just with gravity. (there are powered extensions too)

Gravitrax supports a similar kind of creative spirit as lego. For me, it's actually more fun since it's dynamic by default.

Chicago 2024: https://youtu.be/bv8I3jQUOek

GBC specification - https://www.greatballcontraption.com/wiki/standard

It's also interesting looking at its evolution...

Chicago 2014: https://youtu.be/qHQZcRPqUkY

I feel poor looking at this.

That is completely mesmerizing!

How do they get all the pieces? Are there programs like certified Lego professional or do they have to get every piece at consumer prices?

I can’t comment in the specific of this case, but in general adult LEGO builders will acquire pieces through a range of methods - the biggest being bricklink - a website where independent sellers sell individual pieces, often which they’ve ‘parted out’ retail sets to acquire.

LEGO has a similar service (‘pick-a-brick’), or in LEGO stores there is a ‘brick wall’ where you can pick up a small range of individual pieces (sold by volume - i.e. you fill up a box of pieces) and if you ever find yourself near Ulm, LEGO-land Deutschland has a physical location where you can buy pieces by mass.

But in summary, I don’t think there is a magic bullet - it’s an expensive hobby!

(Oh, and in case it’s unclear, in this case by LEGO pieces I mean all of LEGO/DUPLO/Technic).

This is a great way for some people to play in public but still keep a work play wall up by following one simple rule: Only Legos. If you want to break the rule, a maker faire is a better venue. I think GBC is really cool to see, but I would feel like I was wearing hand cuffs if I tried it.

Reading that the GBC standard specifies 1 ball per second, it’s fun to imagine a module that puts 1,000 balls in slow moving storage, taking 15 minutes to warm up and cool down

https://youtu.be/jxMMtIxDrGk?si=dMKyJueGM5kKwRbz&t=55

I would also recommend: 30 - A LEGO GBC Module to test Compliance with the Standard https://youtu.be/Wu3gQLWqm-4

Great way to get a maximum traversal rate per module added to the spec.

There was one at BrickCon in Bellevue, WA last week! It’s my favorite part of the show. Always reminds me of queueing theory and distributed systems.

I just went to Brickfest in San Jose, and was so sad they didn't have a GBC! It was the number one thing I was looking forward to.

wait, what? when was it?

Two weekends ago.

Thanks.. will have to keep an eye for the next one. Had never heard of Brickfest

Brickfest is more of a traveling attraction. The local convention was Bricks by the Bay - they had the GBC in 2023, but the convention is on an indefinite hiatus. I wish it were easier to see where upcoming GBC's would be,

The infinite domino contraption is great!

Oh man, I want to build one with my kids

At Brickworld, they have workshop modules that are fairly simple to make and get involved with GBC.

For example, the 2022 module - https://youtu.be/AO-5eH7vHTM

https://www.greatballcontraption.com/gbc-instructions

Build four of them and you could run them in a loop.

OT: whenever I play Lego with my kids these days, I cannot help but to be slightly disappointed by the number of very specialized brick shapes there are today. Of course, this allows you to build a lot of things that weren't possible before. But I do appreciate the simplicity of the Lego box sets in my own youth. Limitation can also spark creativity.