Subject:
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Re: pneumatics
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Newsgroups:
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lugnet.robotics.handyboard
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Date:
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Mon, 16 Mar 1998 17:42:44 GMT
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Original-From:
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Brett Anthony <anthonyb@ecsSPAMCAKE.csus.edu>
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Viewed:
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1431 times
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At 11:03 PM 3/15/98 -0600, you wrote:
> does anyone know of a good sourec for pneumatics? Im especially interested
> in smaller pneumatics, like those about 1-2" long, with a stroke of 1-1.5"
>
> Thanks!
> phil
Small pneumatics are tough because commercial actuators are (A) expensive
and (B)they assume a stationary machine tied to "shop air", i.e. miniature
mobile compressors/regulators/receivers are nonexistant.
HOWEVER; you still have 3 good possibilities:
1. Tower Hobbies (I don't have their address 'cause I'm at work, but will
send it if you need) or any large RC aircraft hobby store will have a supply
of actuators, control valves, regulators, sequencers, etc. for pneumatic
landing gear. This stuff has the added advantage of already being designed
for RC servo control, so running it with the HandyBoard is relatively
simple. RC aircraft pneumatic systems use standard PEET plastic soda pop
bottles for air receivers. You charge the receiver with a tire pump; don't
worry, these bottles will hold 50PSI safely (actually, 200PSI proof, but
don't try it).
2. Lego pneumatics are surprisingly capable, although their pump doesn't
make much volume. You can control the valves with RC servos, or more simply
by using very small solenoids; which ARE hard to find, but if you prowl the
electronics surplus markets you will turn up some cuties. BTW Will, Lego is
made almost exclusively from ABS.
3. fischertechnik has made a pneumatics line for years, in fact the Lego
pneumatic stuff is er... "patterned" on the ft stuff. The ft pump is
larger, but the valves in the recent sets are simple 3-way deals, like Lego.
Earlier ft pneumatics sets had much sexier valves and elaborate sequenceing
cababilities. These may still be available as parts, but I havn't checked
recently.
The problem with both Lego and ft is that there is no control on the
supply pressure, i.e. the pump runs all the time. So when you're not
actuating, the drive belt slips and the motor runs near stall. This just
EATS batteries and belts. I made a receiver from a small shampoo bottle and
devised a simple pressure switch to control my pump, and it works fine. I
use fischertechnik, but the same sort of thing should be doable with Lego.
Brett Anthony
Research Technician
School of Engineering and Computer Science
California State University, Sacramento
e-mail: anthonyb@ecs.csus.edu
phone: (916)278-6253
fax: (916)278-5949
address: Brett Anthony
E&CS, CSUS
6000 J St
Sacramento CA 95819-6023
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Message has 1 Reply:
 | | Re: pneumatics
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| I think it was the crazy guys in Austin (the ones that put on Robofest) that had a 'portable' air reservoir that consisted of a 2 liter coke bottle, a relief pressure valve and tubing. The coke bottle was filled about a third of the way with water, (...) (27 years ago, 17-Mar-98, to lugnet.robotics.handyboard)
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