View Full Version : Fluid Pressure Sensor

04-04-2017, 09:58 AM
I am a bit stuck in another project on how to measure fluid pressure electronically. I cant seem to find any sensors online for it. I was thinking about using a pushrod with a spring on the end and then a force sensor. But i feel that this will be full of inaccuracy. Are there any fluid pressure sensors that can interface with arduino and if so what is their price range?

Thank you very much

04-04-2017, 10:58 AM
I am assuming you meant liquid, since there are plenty of gas pressure sensors available for arduino (cheap SMD altimeters). Search digikey for pressure sensors with a maximum operating pressure greater than 300kPa and you will find many sensors capable of handling liquids. Which liquids are safe to use with the sensor depends on the membrane isolating the sensor element, so have to read the datasheet and maybe contact the manufacturer if directed by the datasheet. Most of the less expensive sensors provide only a small ~100mV output that requires external amplification and temperature compensation, but slightly more expensive versions include all of the amplification and conditioning within the sensor.

04-05-2017, 05:36 PM
Oops, clicked the wrong reply button the first time. Original message:
"Thank you very much, that was very helpful. Now for calibrating the sensor, can i use air with an inline mechanical pressure gauge to develop my calibration curve or will that membrane prevent this from working due to compressibility or density?"

04-05-2017, 06:20 PM
Pressure is pressure, so in general, the compressibility and density response would be the same between fluids and gasses. (Note: college physics recollection here; I haven't dealt with these sensors in forever!)
The main problem as I recall would be if your membrane is permeable to gas but not fluid, in which case the pressure would leak out. You have to check the data sheet for the sensor you get for specifics.
In general, manufacturer's data sheets are a glorious source of information about gadgets and widgets you use!

04-05-2017, 08:54 PM
Thats what i was wondering, if the membrane messes up the ability to measure pressure since air can compress and slip through smaller holes

04-05-2017, 09:09 PM
If there is any internal electronics in the sensor, then it is very like that it has been tested and calibrated at the factory using dry air.