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Gear logic operations

  1. Jan 2, 2013 #1
    Hello all.

    Just a quick question about logical operations gears can preform. I know if you have a large gear turn a small gear, the center of the small gear will spin faster than the large. But are there any other logic operations that gears can preform?

    Thank you for viewing.
  2. jcsd
  3. Jan 3, 2013 #2


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    Staff: Mentor

    Here is a wikipedia page with information and links about Mechanical Computers:


    A good friend of mine at HP Labs had a lot of involvement in the investigation of the old Antikythera mechanism (astronomical calculator) referenced in that article.

    You might also get some ideas from this website with mechanical animations -- you can sure do a lot with creative gear mechanism designs!


  4. Jan 4, 2013 #3
    Very neat! I found that second link of yours particularly fascinating! Thank you!

    Another question comes to mind when I take a look at those mechanical computers. Is is possible to make logic gates such as NOT, OR and NAND out of just gears and levers and such?
  5. Jan 4, 2013 #4


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    Staff: Mentor

    Yep. Just use Google to search on Mechanical NAND Gate... :smile:
  6. Jan 4, 2013 #5
    Very helpful! Thank you very much!

    I just may have to find a way to tinker with these now...
  7. Jan 4, 2013 #6


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    Staff: Mentor

    Glad to help. BTW, are you familiar with the hobby-scale 3D printers that are available now? You could use one of those to help you build up some demos and prototypes. :smile:
  8. Jan 4, 2013 #7
    I appreciate the suggestion, but I don't think I could afford one of those, even if they are smaller and cheaper than their professional counterparts. But perhaps if I could get per-crafted mechanical parts...?
  9. Jan 5, 2013 #8
    I've been doing many searches on mechanical logic gates, and I have a couple observations. 1: Most of the illustrations are Lego... I have nothing against Lego, but it would be nice to see a more professional example. 2: Nearly all of them involve levers rather than gears, and values "0" and "1" are represented by a poll either retracted or extended.

    I will elaborate a bit one what I am looking for. There was one video I could find on what I am looking for, it is Lego though... "http://www.youtube.com/watch?v=oqLBtKUvGHg".

    Sorry for the Lego illustration, but it was the only one I could find. What I want is the value of "0" to be represented by the axle not spinning, and the value of "1" to be represent by the axle spinning, like in the video. Finally to my questions; how does this NOT gate in this video work, and how might one make an OR gate of similar style?

    Sorry for the most hard to follow post. Thank you!
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