LEGO TECHNIC : 14550


Technic / 14550	14549 \| 14551

Subject:	Re: Brickfest Pneumatic Master and new Pneumatic Gate Circuits
Newsgroups:	lugnet.technic
Date:	Thu, 25 Aug 2005 17:06:31 GMT
Viewed:	5090 times

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

Message has 2 Replies:

		Re: Brickfest Pneumatic Master and new Pneumatic Gate Circuits
(...) 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 (...) (19 years ago, 27-Aug-05, to lugnet.technic)

		Re: Brickfest Pneumatic Master and new Pneumatic Gate Circuits
(...) Yes, I can see how the 2-cylinder design is more cost-effective, particularly since a Backhoe has 10 cylinders and only 7 switches. That allows more cylinders to be used for AND and OR gates, saving the switches for XOR gates. I've done some (...) (19 years ago, 28-Aug-05, to lugnet.technic)

Message is in Reply To:

		Re: Brickfest Pneumatic Master and new Pneumatic Gate Circuits
I think this diagram should explain the differences: (URL) is the N-input differential output AND gate, developed from your sketch. I've used 2 switches for A, to gate the supply so that it doesn't leak. This gives 2+4++4 switches for an N-input (...) (19 years ago, 25-Aug-05, to lugnet.technic)

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