how do I magnify a voltages in a certain range from a sensor?

okay, so the title probably didn't make sense. I wasn't sure how to explain it in such few words. anyways, here's my problem:

-I have a barometer sensor that gives off a voltage range of 0.2v-4.8v, a direct correlation to pressure (15kpa-115kpa), to an ADC (0-5v)
-Most of the data from the barometer is useless... so that I don't waste any of the ADC bits (and to get more accuracy), I'd like to chop off the voltages from 0.2-2.5v, leaving 2.5v-4.8v, and spreading that over a 0-5v spectrum...

Is this even possible?

Thanks!

hi,
I provided a a fellow rocketeer with this circuit, he had the same requirement to measure altitude/pressure.

He has built the circuit and it works OK.

It uses a AD623 opa, the Vref could be simplified if required.

Lets know if this what you have in mind.

EDIT: are you using the MPX4115A or MPX6115 sensor?

Eric

Eric,

Thanks for the quick response. I'm using the MPX4115.

That circuit looks pretty complicated.. Is it difficult to explain?

Thanks
Matt

ghsrocketman said:

Eric,

Thanks for the quick response. I'm using the MPX4115.

That circuit looks pretty complicated.. Is it difficult to explain?

Thanks
Matt

Click to expand...

hi Matt,
I have attached the zipped text of some emails from/to the other rocketman.
They should answer some of your questions.

If you would like to contact the other guy, send me your email address in an email to me, I will forward it on.

Eric