Help me find this pressure sensor for LCD

Pressure sensor

I hope this is in the right forum, apologies in advance if it isn't!

I have a halfords compressor with a digital gauge that will display pressure on an LCD in PSI/bar and shut off at a pre-set value. I've opened this thing up to find out more about the sensor, as I would like to use something similar in another project.

After a LOT of disassembling, it looks like a very tiny transistor with 4 legs, soldered onto a small PCB and connected through 4 core ribbon cable to the control PCB. The sensor is inside a small sealed chamber which is 'exposed' to the high pressure air. Can anyone tell me where to find a sensor like this, and exactly how it works? It appears to be accurate to within +/- 1 PSI and can go up to 250 PSI. Any help much appreciated, sorry in advance if this is in the wrong forum.

Pressure sensor

Hello,
Look this....
https://www.omega.com/toc_asp/subsectionSC.asp?subsection=B02&book=Pressure
Hope it helps

Pressure sensor

Yup, that helped, thanks again Can't find anything there that looks quite like the part in question, but i'm assuming it's a custom design for the application. These compressors are mass produced so it was probably cost effective to do it that way.

Cheers!

Re: Pressure sensor

OK, time for one last question I've had a look around for the cheapest supplier of pressure sensors in the UK. Although they tend to be expensive for most components, I've found these for around the £10 mark at RS. Just in case you get a session ID error, they are part # 235-5891.

Problem is, I've never used this type of sensor before. Looking at the datasheet, it's pretty clear that two pins are for the excitation voltage and the other two are the output. The difference in voltage between these two pins is proportional to the input pressure, so I'll need to use OpAmps to deal with that and give an acceptable voltage level to drive an A/D converter.

The datasheet shows four resistors wired to the sensor, can anyone point me in the right direction for what value these should be? I don't want to order one of these sensors and then fry it

Pressure sensor

Hello,

4 resistors wired?
The four resistors ARE THE sensor.
It is a Weathstone bridge.
Best regards

Pressure sensor

Haha! I thought they were external, my fault Thanks again.