Live data from Hacker News

Logic Gates as Pulley Systems [video]

vimeo.com

1–10 of 20 posts

Re: Logic Gates as Pulley Systems [video]

#3
post #2

That's a cool implementation. It reminds me of domino logic gates: https://www.youtube.com/watch?v=SudixyugiX4 .

This is incredible! After hearing about the MIT tinker toy optimal tic-tac-toe machine[1], I built a half-adder out of dominoes[2] around the same time period as that video and hadn't ever heard of anyone else messing with the concept.

[1] http://museum.mit.edu/nom150/entries/1215 [2] http://imgur.com/a/qq7Kl

Re: Logic Gates as Pulley Systems [video]

#6

Extremely impressive. Almost tempting enough to try and build an adder, but I fear for anything larger than a few gates the concept starts to become clunky to implement (see the gates at the end of the video ..)

I was just wondering how long it would take someone to build an adder. I wouldn't be surprised if someone went for it.

Re: Logic Gates as Pulley Systems [video]

#7
This reminds me of an article written for the April (first) edition of Scientific American many years ago... 1988.

The key thing to look for is the word 'Apraphul' which is the name of the island this was 'discovered' in. The part of the text of the article can be seen at Google Books [1] (many of the articles are behind a paywall)... though finely digging enough, I found it in a forum with part of the article [2]. Still, searching on 'Apraphul Pully' can take you to a number of other interesting pages (including one discussing the article's system).

[1] http://books.google.com/books?id=0Rb5jBg6sJwC&pg=PA117&lpg=P...

[2] http://s10.zetaboards.com/The_New_Coffee_Room/topic/7132776/...

Re: Logic Gates as Pulley Systems [video]

#8

Extremely impressive. Almost tempting enough to try and build an adder, but I fear for anything larger than a few gates the concept starts to become clunky to implement (see the gates at the end of the video ..)

I was just wondering how long it would take someone to build an adder. I wouldn't be surprised if someone went for it.

Adders are curiously simple! You just need a clock, otherwise they kind of break. How you clock weights ... hnng, no ideas there.

Re: Logic Gates as Pulley Systems [video]

#9
post #5

Fun fact, if you can build a NAND gate or a NOR gate, you can derive all other functions. This is called functional completeness.

And you have to be able to compose gates.

Not to detract from a very cool demonstration, but it appears that all of the energy comes from the "inputs" which have to overcome all of the frictional forces in the system. With semiconductor gates, each gate provide the energy required to drive the gates it is connected to which facilitates composition.

Re: Logic Gates as Pulley Systems [video]

#10

Extremely impressive. Almost tempting enough to try and build an adder, but I fear for anything larger than a few gates the concept starts to become clunky to implement (see the gates at the end of the video ..)

A marble adder, also fun: http://woodgears.ca/marbleadd/index.html
Post reply on HN