Ok, it's actually a pressure sensor that has two ports.http://www.freescale.com/files/sensors/doc/data_sheet/MPX12.pdf
It is the same one used in the bellows of a MIDI accordion.
I however need to use it as a breath sensor. I figured that since this sensor is definitely the one that they use in the accordions, (I checked), that just blowing into it ought to put out at least something.
There is a very slight change when I use the sensor without and fancy resistors or op amps.
I believe I need to amplify the signal and so I purchased a few LM324 op amps to play around with, but I'm not getting any change in the value at the data pin.
Of course, I may have the op amp hooked up wrong, but basically, I supplied it with 5+V and ground, and the other three pins are v1 in, v2 in, and v3 out.
Out must be the amplified signal, so that's going to my data pin.
V1 in is getting 5 Volts, and V2 In is getting the v out pin from the breath sensor.
Nothing seems to be happening.