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Lego Logic Gates

Posted by timothy on Wed Dec 15, 2004 06:10 AM
from the three-little-words dept.
Hardware Hacking Toys Science
Thud457 writes "LEGO Logic Gates - It's like Babbage, but with bricks. All the gates except XOR are here, and he goes on to develop a clocked flip-flop. While practical mechanical computers may be out, even at the nanotechnological scale, nanomechanical memory may be in. "
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  • cool (Score:2, Interesting)

    by mirko (198274)
    can one create robots with these or is it only to create simple electronic circuits ?
    I guess these could be combined with mindstorm, couldn't these ?

    • Re:cool (Score:4, Interesting)

      by mirko (198274) on Wednesday December 15 2004, @06:14AM (#11091123) Homepage Journal
      I just realised : this doesn't use electricity, it's some mechanical representation of these electronic devices.
      I however think this still could be used in non electrical devices (quote any "infernal machine" here, like the one that get triggered after Indiana Jones picks a statuette)...

    • Re:cool (Score:5, Funny)

      by flumps (240328) <{matt.corby} {at} {gmail.com}> on Wednesday December 15 2004, @06:24AM (#11091157) Homepage
      Have you seen the size of these things? Putting them in any kind of robot would be kinda stupid.

      "Here I am, brain the size of a planet...made out of lego.."

      I think you'd have more luck with the nano versions of these gates. But good luck trying eh :)

      • The trick would be programming it. You'd need some way of storing information. My thinking would be to use a chain with links denoting one and zero. Then you'd just need a mechanism to read and write the chain.

        And you never thought that automata class was going to come in handy ;-)

  • Lego-4 3 GHz, here we come! (Score:5, Funny)

    by Anonymous Coward on Wednesday December 15 2004, @06:13AM (#11091120)
    'Tis but a small step to a 64-bit processor with 2 MB of cache. Of course, the bricks might burn up upon power-up, but it's a small price to pay!
    • Hmmm...3 GHz...

      Since the push/pull distance for the gate outputs described is about one LEGO stud length, or 8 millimeters.

      At 3 GHz we have a cycle every 3e-10 seconds (~300 picoseconds), and so a mean speed of 8 mm / 300 ps, or nearly 25 million meters per second. That's nearly 10% of the speed of light, so you're going to have to watch out for relativistic effects. :D

      I don't know the mass of the LEGO axles used in the figure, but if they're 5 grams apiece, then each would have a kinetic energy of about 1.5 terajoules. That's about the same as the kinetic energy possessed by a Nimitz class aircraft carrier travelling at 300 knots.

      If you think P4s have heat dissipation issues....

  • No need for XOR (Score:5, Informative)

    by Anonymous Coward on Wednesday December 15 2004, @06:16AM (#11091126)
    XOR can be constructed by combining other gates. You acctually just need NAND-gates to be able to create any other gate or larger structure.

    • Re:No need for XOR (Score:4, Informative)

      by ricotest (807136) on Wednesday December 15 2004, @06:27AM (#11091166)
      However, while NAND is the cheapest gate to make with silicon, it's quite a hefty Lego structure. So alternatives would be more desirable.
        • XOR should be easy in principle, though it would require springs, and I'm struggling to think of lego pieces with springs....

          Anyway, take a long brick, put it on a horizontal pivot. Use horizontal motion of other bricks to push either end of the brick in such a way that it trips some sort of switch. Put such a switch on either end. (If you don't want to use switches, find a way so that both ends can push simultaneously on something built like a space bar so when you push on either end, the center alway

    • The road to hell is paved with NAND gates.

      -- /usr/bin/fortune

    • Re:No need for XOR (Score:4, Insightful)

      by Taladar (717494) on Wednesday December 15 2004, @07:43AM (#11091353)
      With this being mechanical Gates suffering from friction using gates to emulate other gates isn't desirable.

          • Re:WOW (Score:4, Informative)

            by Ashtead (654610) <aashtead@broad p a r k .no> on Wednesday December 15 2004, @08:33AM (#11091545) Journal
            I'd say that depends on the particular kind of logic circuit. DTL and original TTL were natural for NAND-functions, just add another emitter in the input stage for TTL, or equivalently, another diode for DTL to add more inputs. A one-input gate would be the NOT gate. NOR-functions would be achieved by parallelling transistors in the second stage of the gate, hence adding another input then meant adding an another entire input stage also. This would be more space-consuming an thus more expensive.

            For ECL, the situation is the opposite, since here everything is mostly transistor stages connected in parallel, as well as generally available true and complementary outputs, so the NOR or OR functions are the most common. Add another transistor in parallel for each additional input, and outputs can be tied together in some cases, forming more OR-functionality. With inversions, the necessary AND and NAND functions may be generated as per DeMorgans theorem.

            The situation for NMOS, PMOS and RTL are similar to the one for ECL: transistors in parallel for the basic NOR function are generally preferred to transistors in series for the NAND function.

            In CMOS circuits, NAND and NOR are about the same in complexity, it is a matter of parallel-connecting the P-channel transistors and series-connecting the N-channel transistors for a NAND function, and vice versa for the NOR function.

            Here is some information about the internal connections of RTL, DTL, TTL, ECL and CMOS circuits. [asic-world.com]

  • Can it play .Ogg files?
  • ... just as long as we don't get a little lego man instead of that bloody paperclip I don't really care

  • Will BSD run on it? (Score:3, Funny)

    by Anonymous Coward on Wednesday December 15 2004, @06:20AM (#11091143)
    Let us know when theres a NetBSD for it so we can build a LegoLAN

  • Mechanical Analogs (Score:5, Interesting)

    by nyekulturniy (413420) on Wednesday December 15 2004, @06:22AM (#11091148)
    There may be no obvious immediate use for mechanical analogs of digital circuits, when digital circuits are orders of maginitude faster than mechanical circuits, but dismissing the idea out of hand reminds me of old scientists telling the newspaper that "There's no need for flying machines here!"

    Besides, a steam-powered computer would be really fun to build!

    • I guess the best use of mechanical digital circuits would be if you don't care about speed but want something almost indestructable. Build the cogs out of titanium with teflon coating for lubrication and who knows what the possibilities could be. Just think of the dangerous places you could send a robot built out of this stuff. Output could be an issue though unless you have the thing wave little semaphore flags and some guy with binoculars notes them down!

    • Re:Mechanical Analogs (Score:5, Informative)

      by Ford Prefect (8777) on Wednesday December 15 2004, @06:33AM (#11091190) Homepage
      There may be no obvious immediate use for mechanical analogs of digital circuits, when digital circuits are orders of maginitude faster than mechanical circuits

      If you scale things down a bit [wikipedia.org], mechanical 'circuits' can become a lot faster - and combined with the electrical properties of the components there might be an interesting hybrid some point in the future.

      Still, using Lego is just a little insane, and there is the minor problem of a '1' or a '0' slowly degrading into '0.5's further along the Lego logic chain... :-)

      • Re:Mechanical Analogs (Score:4, Insightful)

        by LWATCDR (28044) on Wednesday December 15 2004, @10:48AM (#11092689) Homepage Journal
        "Still, using Lego is just a little insane,"
        actually it is very sane. It makes a great learning tool. I remember building simple logic gates with my radio shack electronics kit. This lets students build some simple logic "circuits" and see them work with there own eyes.
        Not to mention that mechanical skills in the US really seem to be going down hill. When was the last time you saw a kid build his own skateboard, tree house, or model airplane.
    • There may be no obvious immediate use for mechanical analogs of digital circuits

      I think that they can be used to teach young children the basics of electronics. It will be fun as well as education.

    • My old college had a steam powered computer

      - an Elliot 803 powered by a 3 cylinder marine compound, driven from the central heating boilers (North London Polytechnic in Hollway Road)

    • > Besides, a steam-powered computer would be really fun to build!

      Are you nuts? Valve's [steampowered.com] DRM system eats up 25-30 megabytes even when HL2 isn't running. Do you have any idea how much Lego costs these days? :)

  • Dudududupe (Score:3, Funny)

    by Repugnant_Shit (263651) on Wednesday December 15 2004, @06:23AM (#11091152)
    Next, CmdrTaco will build a duplicate article out of Dupe-lo blocks!
  • "The previous bandwidth issues should be solved now that I have a new server." ...or not...
  • Before you read on, if you have had trouble accessing this page then please accept my apologies. The previous bandwidth issues should be solved now that I have a new server.

    That is, until /. arrived....5:30am and the site's already running slow. How much longer you think it will hold up?

  • Imagine (Score:2, Funny)

    by Anonymous Coward
    .. a Bionicle cluster of these ...

  • "Apple iBricks Launch delayed (Score:4, Funny)

    by goldcd (587052) * on Wednesday December 15 2004, @06:42AM (#11091211) Homepage
    and projected power decimated."
    A spokesman said Steve would only use the white bits of Lego.
  • How long will we have to put up with this LEGO monopoly? Will Megablox answer this challenge? That upstart Knex, perhaps?

    Back in my day we had to build our mechanical analogs of digital circuits out of Tinkertoys! And we liked it! What's this new fangled "plastic" stuff anyway. Wood! that's the way to go.

    On a slightly more serious note: If we had built some of these in my CS3?? class instead of just diagraming them on paper I might have paid more attention. But I doubt it.
  • I would love to play with logic gates like these. Trying to create early computers, or just a simple "addition machine" with a series of logic games would be of immense intellectual interest.

    *But* physical stuff is a pain; has anyone put together a program that allows me to simulate basic electronic gates, and "build" these things. It would help me understand a lot better how computers' internal logic work.

    Thanks,

    Robert

  • Speed? (Score:3, Funny)

    by the_Twisted (838440) on Wednesday December 15 2004, @06:59AM (#11091252)
    At how many (K)hz will this thing operate when it's finished? How many FLOPS will it achieve? Could you overclock it by adding oliveoil to the gears?

  • This post was lifted verbatim from Metafilter (Score:5, Interesting)

    by Jude T. Obscure (721864) on Wednesday December 15 2004, @07:00AM (#11091254)
    Have a look - it's identical [metafilter.com].

  • Friction Losses and Gain Stages (Score:4, Interesting)

    by Fleetie (603229) on Wednesday December 15 2004, @07:29AM (#11091322) Homepage
    There is much friction inherent in these, and as shown, no "gain stages" to overcome these losses. So the "fan-out" would be appalling as implemented here. This would preclude their use to build anything other than the simplest logic constructs. However, I think it would not be too hard to add "gain stages" to act as "buffers", which could, for example, use falling weights to act as "supply rails" to increase "fan-out", thereby facilitating construction of far more complex circuits. Martin

  • A couple problems. (Score:5, Interesting)

    by PenguiN42 (86863) <taylok2@@@alum...rpi...edu> on Wednesday December 15 2004, @07:54AM (#11091375) Journal
    As another poster mentioned, there's no gain in these devices, so after a few stages of friction loss and imperfections in the mechanisms, the whole thing will lock up. Electronic gates have inherent gain, and thus are resistant to noise and slight differences between gates.

    Another problem is the way his clock works -- the clock has to go to zero before the set or clear bits can change. This won't happen in a real circuit -- generally everything changes just after the clock rises. One solution is some sort of two-phase system, where alternate flip flops use the rising and falling clocks, but I'm not sure how much this would limit the circuits you can build.

    He mentions that "It is possible to build an edge detector for the clock signal. It requires a few more NAND gates. The advantage of doing this is that it no longer matters when the clock signal goes back to 0 and the indeterminant state is avoided." But I want to see it in action before I believe it.

    Giving the gates gain may be possible, too, but it would require powering each gate, either with electrical power or some sort of funky mechanical setup.

    • Re:A couple problems. (Score:4, Informative)

      by RPI Geek (640282) on Wednesday December 15 2004, @09:44AM (#11092052) Journal
      Giving the gates gain may be possible, too, but it would require powering each gate, either with electrical power or some sort of funky mechanical setup.

      When I read the title of this article, I tried coming up with a design in my head of how I would do this, and my idea is to make the clock pulse out of a rotating shaft with cams (easy enough for Lego pieces). The cams are what would actually power the pieces, thereby eliminating the effects of backlash and fanning. The only problem comes with a lack of torque, but it would be easy to simply tie in more motors (or more hand-cranks) to get more power down the line. I think that this is a more elegant solution than having a person manually slide a shaft back and forth for the clock pulses.

  • This is sort of cool, but... (Score:4, Insightful)

    by pclminion (145572) on Wednesday December 15 2004, @11:59AM (#11093513)
    Although I find this cool from a purely geek standpoint, and while I realize that the guy probably doesn't intend this as a practical device, I can't help but wonder... WHY use a binary representation?

    With electronic computers, binary makes sense. A capacitor is either charged, or not charged. A transistor is either conducting, or not conducting. It's HARD to make electronic devices with some fixed number of states other than two (let's disregard analog computation, with its infinite number of states, for now).

    Yeah, this thing is like Babbage's machine in the sense that it computes mechanically, but Babbage's machine wasn't binary. It's EASY to make multi-state mechanical devices.

    We shouldn't let our current computer technology make us too narrow-minded when designing new computer technologies. Binary representation is no Holy Grail, it's merely a convenience in the world of semiconductor electronics.

  • Speaking of mechanical computers... (Score:5, Interesting)

    by sgage (109086) on Wednesday December 15 2004, @01:10PM (#11094415)
    When I was a kid back in the 60's, I had a toy mechanical computer called 'Digicomp'. It was a funky conglomeration of springs-and-rods-and-plastic-things that you built from a kit, and programmed it by putting little pieces of tube over various tabs to affect the flip-flops.

    To operate it, you pushed a sliding thing in and out (a clock cycle). You could add and subtract and multiply and divide in binary, albeit rather small numbers. Hard to describe this thing, but it was very cool!

    Actually, the following year I got Digicomp II for Christmas, which ran by letting a stream of marbles flow through it by gravity, and these marbles toggled the flip-flops. Very cool again!

    These toys came with excellent little books on Boolean Algebra, and sure taught me a lot about the interface between binary math and physical things. I felt right at home when I started programming 6502's and Z-80's in machine language back in the day...

    Are these things, or anything like them, still around?

    - sgage

    • Re:This was just plain mean (Score:5, Informative)

      by MrNonchalant (767683) on Wednesday December 15 2004, @06:45AM (#11091225)
      MirrorDot appears to be down at the moment. In the meantime I mirrored it here [f2o.org]. Unfortunately my web host isn't that generous so I'll probably take it down very shortly. Those that want to mirror the mirror can grab a zip file copy here [f2o.org]

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