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Subject: 
Solenoid Pnuematic Valve
Newsgroups: 
lugnet.robotics
Date: 
Fri, 15 Sep 2000 16:11:09 GMT
Viewed: 
521 times
  
I have finally found a tiny solenoid valve for use with the RCX.  It fits
into a 2x4 stud brick, and runs off one of the motor outputs.  All I had to
add was a resistor, a zener (the valve runs on 3 VDC), and a diode (reverse
voltage stop).  It's really neat.  Did I mention it fits into a 2x4 brick?

That said, it isn't perfect. ;>(

It's a traditional 3 way valve, not a 4 way ( the Lego valve is effectively
a 4 way valve in that it vents), and as a result is limited to controlling
motion in one direction only.  It would take two to control both extension
and retraction.  Of course the weight of the load, or a rubber band could
supply the return force.

It won't work well under full Lego pressure.  That's partly due to the low
voltage package, and partly the backwards application of pressure to the
N/C port.  To get the cylinder to vent properly, you attach pressure to the
N/C port, and the cylinder to the common.  A 12VDC version is available
rated conservatively at 30PSI, but I don't think the RCX would quite move
it at < 9VDC.

It's tiny, but it still ain't cheap.  I had this one sampled to me, but the
list price for the guts is $29.00.  Quantity discounts don't start until 25
pieces (5%), and to get 25% you'd be buying 1000.  That's a lot of valves,
and $21,750 dollars.....

You could easily fit 6 of them into a 2 x 4 Duplo block....Hmmmm it's only
$180.  I might just have to buy another to get two way control.

I have some pictures, but no web site to post to.  I'd be happy to send out
what I've got.

Jeff

Jeffrey Hazen
North Mill Technology
jeffrey.hazen@northmill.net



Message has 1 Reply:
  Re: Solenoid Pnuematic Valve
 
(...) Was it these valves ? (URL) not, they seem intersting, but I have no information about cost, availibility, efficency with RCX. I just found that in a magazine. Marc Klein A Mindstorms fan. (23 years ago, 9-Mar-01, to lugnet.robotics)

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