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Subject: 
Re: The latest rage in pneumatic computing
Newsgroups: 
lugnet.robotics
Date: 
Sun, 22 Jun 2003 17:30:39 GMT
Original-From: 
Andy Gombos <GOMBOS_2000@EARTHLINK.NETnomorespam>
Viewed: 
2215 times
  
Using the paper tape idea - the input consists of a row of holes and spaces.
The spaces are large enough for a piston end to get through, and change some
part of the meachine on the other side (to store state).

Output could be a piston with a sharp object, that simply punches a hole in
the paper.  Unless you had a very big punch, output could not be easily fed
back into the input.

Reading/Writing the direct state of the RAM is probably going to be a much
easier solution, and use a good deal less parts.

----- Original Message -----
From: "Mark Tarrabain" <markt@lynx.SPAMBLOCK.net>
To: <lego-robotics@crynwr.com>
Sent: Sunday, June 22, 2003 1:18 PM
Subject: Re: The latest rage in pneumatic computing


> Steve Baker wrote:
> > I wonder if there are savings to be made by building the adder from • scratch
> > rather than out of standard XOR/AND/OR gates.
> 
> I thought so too, so I designed one.  See elsewhere in this thread.
> 
> > The big remaining issue is storage - both RAM and ROM.
> 
> Yeah, I thought so too.
> 
> > Whilst you can theoretically build this out of flip-flops - and
> > flip-flops out
> > of standard 2 input logic gates - I can't help feeling that having more
> > than
> > a few dozen bits of storage would consume Lego's entire production of
> > pneumatics!
> > 
> > If you want to build something that can actually run moderately • interesting
> > programs, you'll need a LOT of ROM and at least a couple of bytes of • RAM.
> > 
> > If each bit could be something like an axle pushed through a hole in a • beam
> > with a '1' and a '0' being encoded by the amount of rod sticking out of
> > the hole,
> > then it would be perfectly feasible to build many hundreds of bytes of
> > storage
> > using only the Lego that most AFOL's have in their collections.
> > 
> > ROM could be built identically to RAM but with fixed pegs instead of
> > movable axles
> > 
> > The question is how to address it, read it and write it.
> > 
> > Since we can presumably build a pneumatic 'stepper motor' that would
> > move a long
> > stack of beams up or down one row for each change to it's input, we
> > could step
> > through a list of instructions stored in 'push rod' memory quite easily.
> 
> This is almost exactly what I was envisioning!!!   Cool.  Glad to know
> I'm not the only one psychotic enough to come up with a cockamamy idea. :)
> 
> > With a counter built from a multi-stage pneumatic adder, one could
> > contemplate
> > building a 'jump' instruction.  You're also going to need some kind of
> > pneumatic 'shift-register' to hold the results of additions carried out
> > with
> > your one-bit adder circuit.  (Either that or a LOT of those adder
> > circuits!)
> > 
> > Reading memory would require something like a bank of switches that are
> > flipped
> > by the push-rods or pegs that are protruding far enough.
> > 
> > Writing RAM memory could be done by pistons forming the output of gates
> > simply
> > pushing against the movable axles from one side or the other of the • memory
> > cell.
> 
> Actually, I was thinking that what you could do is make LEGO-ish (maybe
> one dimensional) "punch cards".  And any program's output would be
> "printed" onto another "punch card" for output.  The problem with this
> is that I don't see any simple way to implement this without using a
> light sensor.   Pneumatics can certainly push the axles out of the
> holes, but I'm not sure how you'd use them to read without possibly
> punching more holes in the "punch card", and losing any chance of
> reading what was there in the first place.
> 
> > The question becomes one of how 'pure' you'd like to build your • pneumatic
> > computer and whether you consider the use of geartrains and even • possibly
> > electrical motors to be 'cheating'.
> 
> I'd say it's not cheating as long as you're not using the RCX or some
> other microcontroller to do the work.  Motors and gears are okay as long
> as they are controlled by pneumatic and mechanical logic.
> 
> > > Mark
> 



Message has 1 Reply:
  Re: The latest rage in pneumatic computing
 
(...) Yeah, but that would be the whole idea. Otherwise it would be easy.. just knock out axles where you want a 1 and leave 'em in where you want a zero and let a human being read it. But I was thinking of a situation where the output could be fed (...) (23 years ago, 22-Jun-03, to lugnet.robotics)

Message is in Reply To:
  Re: The latest rage in pneumatic computing
 
(...) I thought so too, so I designed one. See elsewhere in this thread. (...) Yeah, I thought so too. (...) This is almost exactly what I was envisioning!!! Cool. Glad to know I'm not the only one psychotic enough to come up with a cockamamy idea. (...) (23 years ago, 22-Jun-03, to lugnet.robotics)

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