Hi,
I am thinking to use two sensors. One sensor detect a signal +motion and another sensor detect just motion. Is any way I can subtract these two signals?
Thanks
1st method. Digitize both signals and subtract them in software/firmware.
2nd method. Invert the polarity of one of the signals and then add them in analog in a summing OpAmp circuit http://www.ecircuitcenter.com/Circuits/opsum/opsum.htm
3rd method. Use inamp or differential opamp. the signals have to be scaled equally.