Pressure Sensor Design Questions

Yes. Read the specsheet. You'll need an instrumentation opamp which will cost under $5. Appnotes showing ciruits are readily available. Look to Sensym, TI, Burr-Brown, Linear Technologies for details.

Thank you. I read the specsheet on the pressure sensor and it wasnt very helpful. I will look for the application notes as you suggested.

Hi, Wilson. Oh, my. [/Rumsfeld]

First off, spending a little time at the manufacturer's website will dredge up this link, which might be helpful on a couple of fronts:

The tinyurl duplicates the above.

Since a couple percent total accuracy is more than sufficient, you'll probably want to save a few bucks and roll your own instrumentation amp from 3/4 of a quad and a couple of pairs of 1% or 0.5% resistors. Look at the top circuit on page 14 of the venerable National Semiconductor AN-31, "Op Amp Circuit Collection"

Setting things for a gain of 20 or so looks about right -- it kind of depends on what you want to do here.

Also, if this is a senior project, I'm afraid it's a little too simple.

But if you want more help, feel free to post at sci.electronics.basics.

Go Trojans! Chris

Go to

This is the datasheet for the INA128 instrumentation opamp. Look at figure 4 on page 11.

Also search on straingage amplifiers. Pressure sensors are electrically very similar to straingages -- because they are straingages!

Hi! As I used pressure transducers (NOT sensors!) before so I d/l the specs pdf of this item and tried to make sense of the specs. a) the range of output voltages at 3V DC excitation is from 30-120mV at full scale, so where are you? Do you have a standard presure to find out what sensitivity your sample produces? BTW did you excite the sensor when trying to measure anything on output? And don't try to read on grounded probe, you short part of the measuring bridge, a floating AVO is recommended till you have your diff. amplifier functioning. b) Some measuring bridges can accept AC excitation producing AC outputs, much easier on resulting amplification stages. Nothing in specs of this item. c) Important, on any transducer, simple disregard the lower 30% of the scale if you don't have access to calibrating equipment where you can define your own part range sensitivity.

HTH Can go on and on but if you have a querry give a sign.

Stanislaw Slack user from Ulladulla.

Thanks,

No this isnt for a senior design.

A little more info though:

I am wanting to be able to adjust the pressure by pressing an up or down button. I plan on using a microcontroller.

thanks for all of the links guys... now I must get to reading up on them.

Thanks for all the info. If you dont mind I would like to email you and ask a few more questions.

Thanks for the replies and the links guys. I have read most of them and understand what to do.

I really do appreciate it.

John

Update:

Again I thank you guys for your help and direction. I made my own inst. amp and the sensor seems to be working wonderful. I used a POT to set the null offset and another to set the gain. I have tested quite a lot and all seems good.

JWilson