hacked air pressure sesor

Using Arduino Sensors
1

Hi all--

I am working on a project that involves a pressurized vessel, I completed a stepper valve for the supply line, but never really gave consideration to the feedback needed to control it (ie a report back on what the pressure is. Unfortunately, I don't have any "proper" pressure sensors & it seems like they are quite expensive. So I hacked open a digital pressure gauge for standard shop air I had laying around & it seems like everything I need is there, but I know nothing about pressure sensors and need some guidance as to how to hook it up to my arduino system. there are two numbers printed on the the pressure sensor board: 1110-056 & 150-088 neither of which returned any info when searching for them.

I have taken some pictures of it that can be seen @ https://picasaweb.google.com/mtraven/Arduino?authuser=0&authkey=Gv1sRgCOu_4Z2dv-6c0wE&feat=directlink

So if anyone can get me going in the right direction with this &| suggest a different method I might be able to pull off, that would be very much appreciated.

PS not totally sure what the max pressure will be, but I am guessing in the 60-80psi max operating pressure.

edit: I also have the option of taking the leads directly from the sensor, or take them from the display & try to translate the data that controls the display into values in arduino.

2

That looks like a piezo bridge pressure sensor.

80 psi = 5.5 bar. Pressure sensor for the pressure are more expensive.
Cheap pressure sensors are up to 2 bar or so, search Ebay for: pressure sensor mpx

3

Erdin:
That looks like a piezo bridge pressure sensor.

80 psi = 5.5 bar. Pressure sensor for the pressure are more expensive.
Cheap pressure sensors are up to 2 bar or so, search Ebay for: pressure sensor mpx

any idea what pins do what? or the circuit I might need to run it?

4

Two pins (opposite pins) of the wheatstone bridge for the voltage.

Two pins in the middle to a OpAmp (perhaps INA122).

It is possible to connect to the Arduino without OpAmp. It is very inaccurate, Arduino Playground - SPX3058D
You could try that to test it.

5

There are a number of test points on the circuit board. It would be worth your time to stick a meter on them and see if any output an amplified voltage that corresponds with the pressure applied.

6

mtraven-

Did you end up getting this to work? What was the design and result?

Thanks

7