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Subject: 
Re: A better full adder!
Newsgroups: 
lugnet.technic, lugnet.robotics
Date: 
Fri, 27 Jun 2003 09:47:01 GMT
Viewed: 
1555 times
  
In lugnet.technic, Mark Tarrabain wrote:
Kevin L. Clague wrote:
AND takes 1 piston + 1 switch using your design.

XOR takes 1 piston + 2 switches using my design.

Ah... it took me a while to figure out what you were doing, but I see
now... (reviewing your pics)

If your inputs to the XOR were A and B, you use A to drive the piston,
and require the presence of both B and NOT B to make the piston move.  I
see what you were doing now.

Yes.  B and NOT B into the mux formed by two switches that are arranged to never
release.


Yeah... after my first round of pneumatic trials failed abysmally, I
tossed the idea of using or requiring inverted logic.

But with LEGO pneumatics you can typically get it for free.


Two half adders (2 + 6), plus one OR gate (1 + 2) totals 3 + 8.

So you can build a full adder with only 8 switches??? WOW.

Yes.  When I wrote my post up yesterday I'd forgotten that I needed NOT B as an
input.

On a practical note, this big burst of pneumatic logic innovation we've had is
allowing me to make more advanced pneumatic walkers that were huge designs
before, and very compact now.  I've got a paper design that I hope to have
implemented soon.

Part of my root motivation in the boolean logic effort was to learn all I could
about designing with pneumatics so I could make better bipeds.


Mark

Kevin



Message has 1 Reply:
  Re: A better full adder!
 
(...) Not sure what you mean. If an output isn't producing any airflow, how do you invert that? BTW, I've been wracking my brains on this for several hours now, I can't figger out how you possibly could have built a full adder with only 3 pistons (...) (21 years ago, 27-Jun-03, to lugnet.technic, lugnet.robotics)

Message is in Reply To:
  Re: A better full adder!
 
(...) Ah... it took me a while to figure out what you were doing, but I see now... (reviewing your pics) If your inputs to the XOR were A and B, you use A to drive the piston, and require the presence of both B and NOT B to make the piston move. I (...) (21 years ago, 26-Jun-03, to lugnet.technic, lugnet.robotics)

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