Reading Freescale MPX2202 series pressure sensor

hi,

i've spent last 2-3 weeks trying arduino read pressure sensor, no avail. here's datasheet:
http://www.freescale.com/files/sensors/doc/data_sheet/mpx2202.pdf

i have part: mpxm2202gs. here's i've tried far:

• connect + vout arduino analog pin. i'm able read 1 value time, regardless of pressure, due resolution of adc


• use 1 op amp in "differential" configuration. i've tried 3-4 different calculators resistor values, of them show different outcomes. i've tried experimenting 5 different gain configurations, of them same output voltage, , not change pressure change


• using 2 op amps described in application paper @ freescale site. http://cache.freescale.com/files/sensors/doc/app_note/an1586.pdf?fpsp=1&wt_type=application%20notes&wt_vendor=freescale&wt_file_format=pdf&wt_asset=documentation. i'm getting same voltage, regardless of pressure.


• instrumentation amplifier (which supposed precise , correct way interface sensor), still no luck. more on below.

so, think have connected incorrectly instrumentation amplifier, should work purpose. using part:
http://www.analog.com/static/imported-files/data_sheets/ad8293g80_160.pdf

+5v voltage supply both sensor , amplifier. tried connecting in+ +vout , in- -vout, i'm getting ~5v on adc output. tried inverse: connecting in+ -vout , in- +vout. still getting ~5v on adc output pin. see attachment amp connection schematic. had create own symbol though. , 4 wires coming left - go pressure sensor connector. note wiring reversed in cable, goes (top bottom) pin 3, 2, 4, 1 on pressure sensor.

when disconnect +vout , -vout amplifier, reading between 0 , 5mv between 2 terminals. both around 2.5v ground or vs. when connected amp, i'm reading 3v on in- , 5v on in+.

i'm out of ideas @ point. see wrong connections? ideas on can tried next?

thanks help! , apologize length, trying put know out there.

you'll need intrumentation amp  or rail_to_rail op-amp. (as application note)
schetch shows 30x ampl, u need more. -> change 2 of resistors
calibrating unit can done software..

Arduino Forum > Using Arduino > Sensors > Reading Freescale MPX2202 series pressure sensor

arduino