5 ms·

Predicting the tide with an analog computer made from Lego

154 points by RansomStark 5y ago

thbszzlrd 5y ago
themaineking 5y ago
Syonyk 5y ago
Excellent. I do feel like there's been a bit of a rejection of the polished, streamlined, "Facebook/Reddit" internet of late, and I love reading articles like this. "I wonder if I can do..." ponderings, followed by a wonderfully absurd, but still mostly functional way of doing it, that involves going down all sorts of fun little rabbit holes to work around nonsensical but entertaining constraints like "Lego gears don't exist in an infinite number of forms." Though as much as it doesn't need to be https, I still think random personal sites should be https. It makes it harder to inject random bonus conntent in the responses, and I include any form of modification there, not just malicious - ISPs have been known to make changes to add their own little ad banners in the past. Denver International is particularly bad at this, or at least used to be.
- throwawayboise 5y ago
  > "I wonder if I can do..." ponderings I feel a bit sad when I read about this sort of stuff. At one time it was the sort of thing I would do, but nothing seems interesting or motivating enough these days. My first thought is "wow that would take a lot of time" and I abandon the idea.
  - batch12 5y ago
    Maybe start again with something small or something that starts halfway through that you can see to completion. Maybe you don't have to build a sailboat to learn to sail. Maybe I am talking to myself...
ape4 5y ago
Perhaps he could have 3D printed the exact gear sizes needed.
- kingcharles 5y ago
  That was my immediate thought - the poor guy is stuck working with canon Lego gear sizes which makes his job way harder. 3D printing would have solved this, but then produced something not replicable with regular Lego sets.
abalaji 5y ago
The author mentions they were inspired by the Veritasium video on the same topic (without the Lego). [1] I thought I'd link the previous HN discussion. [2] [1] https://www.youtube.com/watch?v=IgF3OX8nT0w https://www.youtube.com/watch?v=IgF3OX8nT0w [2] https://news.ycombinator.com/item?id=29645610 https://news.ycombinator.com/item?id=29645610
raldi 5y ago
I’m having trouble figuring out what the output mechanism is.
- sparky_ 5y ago
  Same, it looks like a big rube goldberg machine without that context.
- detaro 5y ago
  the string going downwards (visible in the last picture), he shared a clip of an earlier stage on Twitter where it's clearly shown: https://twitter.com/pepijndevos/status/1487445805879500800 https://twitter.com/pepijndevos/status/1487445805879500800
neoneye2 5y ago
Awesome. Please make a longer video, explaining how it works.
usrusr 5y ago
To save you some typing: this is the first hit if you google antikythera mechanism lego: https://m.youtube.com/watch?v=RLPVCJjTNgk https://m.youtube.com/watch?v=RLPVCJjTNgk
zokier 5y ago
Lego is interesting, because on the other hand it is very accessible (to a degree), but at the same time it tends to shift projects from making a thing to working around the limitations of Lego. Kinda reminds me of bash programming, it has similar characteristic of being attractive because it is there, but then actually engineering around the limitations of bash becomes quite the exercise once you start implementing stuff.
- jacobolus 5y ago
  Working around the limitations of your materials (including skills, tools, budget, support network, ...) is the story of making anything. Legos are intended as a kids’ toy, and a few years of experience working within their capabilities and constraints to build increasingly tricky projects is great experience for kids, with lots of skills transferrable to any other kind of creative technical work.
tombert 5y ago
I'm a big fan of "mechanical solutions to computer problems." I think it's extremely interesting to see how hard it is to encode logic pre-transistor, and makes me feel spoiled today (in a good way). My favorite example is the writer automaton [1]. It's something that never stops to impress me, just because it's something that wouldn't be that hard nowadays, but must have required effectively PhD levels of understanding to do pre-computer. [1] https://youtu.be/OehTO9l1Hp8 https://youtu.be/OehTO9l1Hp8
rootsudo 5y ago
And in a couple centuries they're going to find this at the bottom of the sea and wonder what went wrong. (In reference to the "greek" computer that tells tides/lunar cycle and planets.) If plastic will last that long, (I think it does? But still, It is fun and I like these lego projects! I want to buy a few sets and recreate it.
- rdc12 5y ago
  Solid plastic might, but would moving water and impacts result in the bricks separating?
xaedes 5y ago
In the video comments he posted a link [1] to his blog where he explains the design process using simulated annealing. Amazing how close he got to the targeted final ratios using only a sequential gear train. [1] http://pepijndevos.nl/2022/01/30/predicting-the-tide-with-an-analog-computer-made-from-lego.html http://pepijndevos.nl/2022/01/30/predicting-the-tide-with-an...
kmstout 5y ago
Reminded me of this talk by Charles Petzold: https://www.youtube.com/watch?v=O-N5DuEUap8 https://www.youtube.com/watch?v=O-N5DuEUap8
mhb 5y ago
Mechanical computer for computing Fourier transforms: https://www.youtube.com/watch?v=NAsM30MAHLg https://www.youtube.com/watch?v=NAsM30MAHLg
kippinitreal 5y ago
This is what I’m here for! Awesome work, super cool to see and read how you did it.
justinator 5y ago
This was an excellent video on how this all works, https://www.youtube.com/watch?v=IgF3OX8nT0w https://www.youtube.com/watch?v=IgF3OX8nT0w
lmm 5y ago
Very cool. Reminds me of the mechanical Easter clock in Strasbourg cathedral.

154 points by RansomStark 5y ago

Excellent. I do feel like there's been a bit of a rejection of the polished, streamlined, "Facebook/Reddit" internet of late, and I love reading articles like this. "I wonder if I can do..." ponderings, followed by a wonderfully absurd, but still mostly functional way of doing it, that involves going down all sorts of fun little rabbit holes to work around nonsensical but entertaining constraints like "Lego gears don't exist in an infinite number of forms." Though as much as it doesn't need to be https, I still think random personal sites should be https. It makes it harder to inject random bonus conntent in the responses, and I include any form of modification there, not just malicious - ISPs have been known to make changes to add their own little ad banners in the past. Denver International is particularly bad at this, or at least used to be.

throwawayboise 5y ago
> "I wonder if I can do..." ponderings I feel a bit sad when I read about this sort of stuff. At one time it was the sort of thing I would do, but nothing seems interesting or motivating enough these days. My first thought is "wow that would take a lot of time" and I abandon the idea.
- batch12 5y ago
  Maybe start again with something small or something that starts halfway through that you can see to completion. Maybe you don't have to build a sailboat to learn to sail. Maybe I am talking to myself...

ape4 5y ago

Perhaps he could have 3D printed the exact gear sizes needed.

kingcharles 5y ago
That was my immediate thought - the poor guy is stuck working with canon Lego gear sizes which makes his job way harder. 3D printing would have solved this, but then produced something not replicable with regular Lego sets.

abalaji 5y ago

The author mentions they were inspired by the Veritasium video on the same topic (without the Lego). [1] I thought I'd link the previous HN discussion. [2] [1] https://www.youtube.com/watch?v=IgF3OX8nT0w https://www.youtube.com/watch?v=IgF3OX8nT0w [2] https://news.ycombinator.com/item?id=29645610 https://news.ycombinator.com/item?id=29645610

raldi 5y ago

I’m having trouble figuring out what the output mechanism is.

sparky_ 5y ago
Same, it looks like a big rube goldberg machine without that context.
detaro 5y ago
the string going downwards (visible in the last picture), he shared a clip of an earlier stage on Twitter where it's clearly shown: https://twitter.com/pepijndevos/status/1487445805879500800 https://twitter.com/pepijndevos/status/1487445805879500800

neoneye2 5y ago

Awesome. Please make a longer video, explaining how it works.

usrusr 5y ago

To save you some typing: this is the first hit if you google antikythera mechanism lego: https://m.youtube.com/watch?v=RLPVCJjTNgk https://m.youtube.com/watch?v=RLPVCJjTNgk

zokier 5y ago

Lego is interesting, because on the other hand it is very accessible (to a degree), but at the same time it tends to shift projects from making a thing to working around the limitations of Lego. Kinda reminds me of bash programming, it has similar characteristic of being attractive because it is there, but then actually engineering around the limitations of bash becomes quite the exercise once you start implementing stuff.

jacobolus 5y ago
Working around the limitations of your materials (including skills, tools, budget, support network, ...) is the story of making anything. Legos are intended as a kids’ toy, and a few years of experience working within their capabilities and constraints to build increasingly tricky projects is great experience for kids, with lots of skills transferrable to any other kind of creative technical work.

tombert 5y ago

I'm a big fan of "mechanical solutions to computer problems." I think it's extremely interesting to see how hard it is to encode logic pre-transistor, and makes me feel spoiled today (in a good way). My favorite example is the writer automaton [1]. It's something that never stops to impress me, just because it's something that wouldn't be that hard nowadays, but must have required effectively PhD levels of understanding to do pre-computer. [1] https://youtu.be/OehTO9l1Hp8 https://youtu.be/OehTO9l1Hp8

rootsudo 5y ago

And in a couple centuries they're going to find this at the bottom of the sea and wonder what went wrong. (In reference to the "greek" computer that tells tides/lunar cycle and planets.) If plastic will last that long, (I think it does? But still, It is fun and I like these lego projects! I want to buy a few sets and recreate it.

rdc12 5y ago
Solid plastic might, but would moving water and impacts result in the bricks separating?

xaedes 5y ago

In the video comments he posted a link [1] to his blog where he explains the design process using simulated annealing. Amazing how close he got to the targeted final ratios using only a sequential gear train. [1] http://pepijndevos.nl/2022/01/30/predicting-the-tide-with-an-analog-computer-made-from-lego.html http://pepijndevos.nl/2022/01/30/predicting-the-tide-with-an...

kmstout 5y ago

Reminded me of this talk by Charles Petzold: https://www.youtube.com/watch?v=O-N5DuEUap8 https://www.youtube.com/watch?v=O-N5DuEUap8

mhb 5y ago

Mechanical computer for computing Fourier transforms: https://www.youtube.com/watch?v=NAsM30MAHLg https://www.youtube.com/watch?v=NAsM30MAHLg

kippinitreal 5y ago

This is what I’m here for! Awesome work, super cool to see and read how you did it.

justinator 5y ago

This was an excellent video on how this all works, https://www.youtube.com/watch?v=IgF3OX8nT0w https://www.youtube.com/watch?v=IgF3OX8nT0w

lmm 5y ago

Very cool. Reminds me of the mechanical Easter clock in Strasbourg cathedral.