Subject:
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Re: LEGO Computers & Logic Gates
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Newsgroups:
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lugnet.technic
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Date:
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Tue, 16 Mar 2004 22:07:50 GMT
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Viewed:
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1884 times
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In lugnet.technic, Martin Howard wrote:
>
> > > I've tried to do it mechanically. So far I've made NOT, AND, NAND, OR,
> > > NOR, a basic NAND latch (flip-flop) and a clocked NAND latch.
> > >
> > > Full details can be found via the LEGO link at my webpage:
> > >
> > > http://www.goldfish.org.uk
> >
> > That is cool Martin! The only thing I'd probably try is doing a NOT gate with
> > just a lever, like a 3L liftarm. May reduce backlash a little.
> >
> > It would be interesting to investigate a way to make them with a +V input of
> > some kind - maybe a motor somehow - that does the switching of the output,
> > similar to the compressor input of the pneumatic models. If that could be
> > done, it might make much larger circuits viable.
>
>
> Thanks for the comments. The 3L liftarm is a good idea. I did originally
> try something similar, but went with the rack and pinion system instead in
> the end.
>
> At the moment I'm trying to simplify the gates to the extent that I don't need
> any cogs at all. If I get that sorted, then the problem of gear slippage
> vanishes and we're back to developing only some sort amplifier that you and
> other have suggested. Although I'm not exactly sure of what you mean by
> using a motor to get a +V input?
This is the same thing as the amplification issue mentioned in other posts.
In our pneumatic gates, we can sometimes use pressure directly from the pumps as
inputs to pneumatic switches, thus providing the "amplification" people are
talking about.
In my most recent pneumatic gate designs, inputs come in as pressure to a pair
of pistons. The pistons control the switch outputs of the gate. The pressure
into these switches comes directly from the pumps. This way pressure only goes
from one switch to one or more pistons (in parallel). This gives us fresh
pressure at each gate level. This "fresh pressure" represents the V+ or
amplification people are talking about.
However, Mark Tarrabain, the most clever pneumatic circuit designer I ever met
that owns no actual pneumatic parts :^), invented a single piston single switch
AND gate. Brilliant. Stringing these gates together into larger circuits
leaves you with the same results.... "fresh pressure" from the pumps is
introduced in very few places in the circuit. In the case of pneumatics, this
means slower switching times, because you are having to fill larger volumes with
pressurized air.
If you are trying to make a mechanical half adder, you might step back and look
at the inputs and outputs without thinking of composing the circuit out of
AND/OR/XOR/NOT circuits.
Mark did this with pneumatics and made the most efficient design. I tried to
beat him, I really did, but every time I bested him, he'd figure out how to use
my new trick to best me.
It is very cool to see other logicians in the technic group.
Great work.
Kevin
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Message has 1 Reply:
 | | Re: LEGO Computers & Logic Gates
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| (...) Thanks for the comments, hints and suggestions. Designing something without the pieces - that's impressive! I think the idea of a motor to amplify the signal could be used and it should be possible to put in some sort of lever that switches (...) (20 years ago, 21-Mar-04, to lugnet.technic)
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Message is in Reply To:
| | Re: LEGO Computers & Logic Gates
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| (...) Thanks for the comments. The 3L liftarm is a good idea. I did originally try something similar, but went with the rack and pinion system instead in the end. At the moment I'm trying to simplify the gates to the extent that I don't need any (...) (20 years ago, 16-Mar-04, to lugnet.technic)
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