Absolute pressure switch

[PlasticsDude]

Does anybody make a cheap ($25) absolute pressure switch? I need something to close a contact at +50mm Hg absolute pressure... I'm guessing the answer is no but thought I'd try...

[DanW]

50mm Hg is almost one atmosphere. You're asking for a barometer Two thoughts: 1) Lots of automobiles come with an absolute pressure sensor, I think the MAP is manifold absolute pressure sensor. If not that, one of those other acronymns. You might experiement with one of those and see if you can condition the signal to get something you can work with. 2) Look through a Dwyer catalog for whatever they've got for liquid manometers. The farmer next door had an L shaped liquid manometer for checking negative pressure in his feeder pig nursery. Use a liquid manaomet and an optical sensor to sense liquid level.

[gravitar]

I think the automotive MAP sensor is a pretty good idea. You would probably want one for a turbocharged engine though, as NA engines don't expect to see anything greater than atmospheric pressure! Here's some info on the ubiquitous GM MAP sensor... http://www.robietherobot.com/storm/mapsensor.htm