Cant find a Pressure Sensor

romartin · Feb 17, 2014

I'm having trouble finding a pressure sensor at an acceptable price ie not more than 50 dollars. I need it to provide an analogue signal which indicates the pressure of air or of steam in the range of 0 to about 8 atmospheres. I think I could manage to encapsulate a naked sensor in a suitable metal case, although it's not something I've done before and I would need help on how to pass the eletrical wires though the case in a reliable and safe manner.
The encapsulated sensor would be attached to a T inserted in an air/steam pipe near to the input or exhaust of an engine under test.

I would be very grateful for any suggestions for a solution or for a search strategy.

tomrux · Feb 17, 2014

Look for a water level sensor from a junked washing machine

Tom R

Noitoen · Feb 17, 2014

You can get a naked one at RS stock nº 235-5891. With a suited amplifier like this one http://www.analog.com/static/imported-files/data_sheets/AD623.pdf you get a good solution.

clivel · Feb 17, 2014

Your best bet would be to find a used scuba dive computer. The depth pressure sensor should be well within your 0 to 8 atmosphere range.

Actually after typing that I did an eBay search, one of the first that came up is an air integrated dive computer offered cheaply for parts, the advantage of an air integrated dive computer is that it has a second sensor for measuring tank pressure - well over 200 bar (about 200 atmospheres).
Clive

terryzilla · Feb 17, 2014

Digikey has bunches of senors. Great company to work with.

Terry

Nerdz · Feb 18, 2014

This is slightly more, but it fits the bill. Ive used these on machines, but not so much the analog part. Its a 4-20 Loop, so you will need to convert that. It should be pretty easy to convert it to a voltage

http://www.automationdirect.com/adc...Pressure_Switches_-z-_Transmitters/QPSH-AN-42

If you want to Go about it yourself,

http://www.mouser.com/ProductDetail...=sGAEpiMZZMvhQj7WZhFIAB6aAQUiwV5UXCTuLqGtSc4=

Looks to be fitting. Here are the search results
http://www.mouser.com/Sensors/Press...0xkevZ1z0vvnk&Keyword=Pressure+Sesnor&FS=True

Mouser is a very good company. Shipping is quick from Texas to the Northeast here.