Subject:
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Re: Binary Pneumatic addition with two pistons
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Newsgroups:
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lugnet.technic, lugnet.robotics
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Date:
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Mon, 9 Jun 2003 21:20:23 GMT
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Viewed:
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288 times
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In lugnet.technic, Mark Tarrabain wrote:
> Kevin L. Clague wrote:
>
> > With LEGO Pneumatics, the pistons are double acting. They have a port to make
> > them expand as well as port to make them contract. This is an alternate
> > solution to your positive and negative pressure, right?
>
> Not exactly... Like you, I was assuming that the position of the
> cylinders would be the input, but I was thinking of using just the
> airflow directly as an output rather than the position of another switch.
>
> As long as the cylinders are made so that it's possible to change their
> position by air intake as well as by air pressure, I was thinking that
> this could work. I suspect that another way of not using negative
> pressure would be to rig an output cylinder with an elastic band so that
> it is extended only when air is blowing into it, but when the air stops
> flowing it goes back. The mechanism I had visualized wouldn't require
> elastic bands.
>
> Or am I totally off base assuming that negative air pressure is doable
> with LEGO pneumatics?
Using a vaccume was possible with old lego pneumatics, but positive pressure is
always used with new LEGO.
>
> I'll be picking some pneumatics up (from bricklink) as soon as I am sure
> I can spare the money to buy a couple dozen parts (I figger making sure
> that rent gets paid might be just a tad more important than playing with
> LEGO).
You got that right.
>
> > My pneumatic logic gates always provide pressure and release, they don't put the
> > output switch into off state.
>
> That's why I was thinking that they could be thought of as SPDT relays.
> I built a small binary adding machine with memory out of relays while
> I was in school in 1978. I've gotten to wondering if I could do that
> with LEGO pneumatics, and I'm suspecting that I can.
>
>
> > I've been working my way there. I've got all the computing elements that I
> > need, except RAM, which would be too expensive to model using pneumatic memory
> > cells.
>
> Yeah... at several bucks a bit, I can see how that could be a problem. :)
>
> > I'm going to try to make memory cards out of technic beams with pins stuck in
> > the holes for ones, no pin means zero. This could be a very difficult thing to
> > build though.
>
> Hrmm... pins? or axles? I would assume the latter because you can slide
> the axles in and out at runtime (one and 0), but the pins are static
> (although I guess they'd be fine for something like ROM).
Pins should be removable or addable. were you thinking of just sliding the
axles?
>
> > I looked up some information on the first microprocessor, the 4004. It was a
> > four bit processor that took 1000 transistors to make. Something on that scale
> > might be doable.
>
> <drool> Er... excuse me. :)
>
>
> BTW, totally off topic here... does anyone else find that their spouses
> think that adults playing with LEGO is, well... a little strange?
My wife is very supportive. She got me started as an adult.
>
> > > Mark
Kevin
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