Subject:
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Re: Brickfest Pneumatic Master and new Pneumatic Gate Circuits
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Newsgroups:
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lugnet.technic
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Date:
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Sat, 27 Aug 2005 11:47:55 GMT
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Viewed:
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4621 times
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In lugnet.technic, Kevin L. Clague wrote:
> Mark,
> I have studied and understand your 3+3 AND gate. A few years ago I made a
> simpler version of the same thing. My design replaces your six switches with
> one switch and mechanical linkages. Here is a picture of this AND gate:
>
> http://www.brickshelf.com/gallery/kclague/Computing/p5280034.jpg
>
> In my 1 AND gate, A and B each control a piston. The two pistons are
> connected base to base, not unlike the pneumatic boom controls in the 8421
> technic crane. One piston is afixed to a frame that also contains a single
> switch. The center of the switch is hooked to the pressure source. Given two
> pistons hooked together in this fashion the total amount of expansion due to
> both pistons can be:
>
> A B Sum Length
> C C 0
> C X X 1
> X C X 1
> X X XX 2
>
> If you extend the handle of the switch by inserting an axle connector and a #2
> axle between the switch handle, and the #1 Angle piece you use to connect to the
> piston, the extension length of the piston is the same length as the throw of
> the switch. The linkage between the pistons and the switch contains rubber
> bands. When both pistons are expanded, the switch handle is pressed away from
> the pistons. When one and only one of the pistons is expanded, the switch is
> pulled toward the pistons. When both pistons are contracted, the rubber bands
> stretch in an attempt to further pull the switch handle closer to the pistons.
>
> By moving the switch closer to the pistons, you can easily make an OR gate.
>
> http://www.brickshelf.com/gallery/kclague/Computing/p5280036.jpg
>
> This is the most cost effect AND gate that I know of that meets all your
> requirements. While too fragile to be put in-situ as a muscle piston, for pure
> computation it has the smallest pneumatic part count.
>
> I don't know that we'll ever see eye to eye on how to count pneumatic parts
> within our gates, but it does not matter to me. Whatever pneumatic circuit I
> make, I will tend to use whatever gate technology that is cheapest and meets the
> need.
>
> I've gained a lot of good knowledge from this discussion, and that is all my
> LEGO pneumatics exploration is about.
>
> I look forward to seeingmore of your designs in the future. I also look forward
> to reading any articles you write for BrickJournal. More is better!
>
> Kev
Hmmm... I think this could possibly be used on something like the 8421 crane,
now that we have proper pieces to fix two cylinders together. Since cylinders
are cheaper and more plentiful (especially in Backhoes) this makes sense for use
on logic boards. The long space required could be a problem in smaller spaces!
I'll consider drawing the new pieces in order to draw end to end AND gates.
I used the rubber band stretching technique on my pneumatic steering mechanism
(to be drawn). Perhaps TLG should make some 24mm cylinders the same girth as
the 48mm ones - short travel but powerful, so that fixing two together gave the
same travel as one 48mm cylinder.
I think I can take 1 switch out of the A input of the AND gate, to make it
1+4++4, and I've also found that inter-stage hoses can be reversed, allowing a
3-input gate to give a high output for any combination of inputs. Reversing the
hoses between stages B and C allows the output to be high on 3 or 5 input
combinations of 8.
Mark
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