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Pressure activated switch

Posted: Sat Aug 15, 2009 1:37 am
by PVC Arsenal 17
A long time ago I recall seeing a pressure activated switch being sold by one of the spud gun stores... possibly BC Arms.

The switch was a small, simple unit with a 1/8" NPT male thread which would connect to the pressure vessel. On the opposite end were two contacts. When the pressure reached a certain point, (IIRC 125psi) the circuit would close.

I've found various sorts of pressure switches but none as compact and simple as this one was. I'm very inexperienced with electronics so if anyone could point me toward something similar to what I saw it would be much appreciated.

I hope to incorporate this switch into a device that is part of an ROV project I'm working on.

Thanks!

Posted: Sat Aug 15, 2009 1:53 am
by jackssmirkingrevenge
you could probably conjure something up yourself with a 1 mL syringe, a spring and some epoxy ;)

Posted: Sat Aug 15, 2009 1:58 am
by inonickname
Erm, modify a 120psi pop off valve to close the switch (but not have it actually release air).. That's how I'd do it.

Posted: Sat Aug 15, 2009 2:07 am
by jackssmirkingrevenge
inonickname wrote:Erm, modify a 120psi pop off valve to close the switch (but not have it actually release air).. That's how I'd do it.
The problem with that is that it would have to be a toggle switch, that would not reset once the pressure goes back down again.

Posted: Sat Aug 15, 2009 2:07 am
by PVC Arsenal 17
Building a switch is always possible, but it doesn't guarantee reliability, consistency, and speed (I need to incorporate a fair number of these into the project)

My search continues!

Posted: Sat Aug 15, 2009 2:17 am
by MrCrowley
I think it might've been Benstern's Spudmall...not sure.

Posted: Sat Aug 15, 2009 2:25 am
by PVC Arsenal 17
MrCrowley wrote:I think it might've been Benstern's Spudmall...not sure.
Yes that was it!

Here it is:
Image

Now to find out more about the switch and hopefully find a similar one that can activate somewhere in the realm of 30psi.

Posted: Sat Aug 15, 2009 7:09 am
by inonickname
Seen as you're a buff with electronics, you could perhaps modify an electronic tire gauge to trigger at a certain pressure.
The problem with that is that it would have to be a toggle switch, that would not reset once the pressure goes back down again.
Note that i said to modify it, so it's a pneumatic ram fighting a spring (and does not exhaust). Once it reaches pressure, it activates the circuit (and does not release air).. Then resets at lower pressures.

Posted: Sat Aug 15, 2009 7:18 am
by Moonbogg
http://www.mcmaster.com/#pressure-switches/=374w9o

here check out mc master on that page.

Posted: Sat Aug 15, 2009 8:46 am
by TurboSuper
http://search.digikey.com/scripts/DkSea ... 80-2041-ND

A little on the expensive side, though.