I have this piezo vibration sensor module from Grove: http://www.seeedstudio.com/wiki/Grove_-_Piezo_Vibration_Sensor
Using this sensor and an arduino device I want to measure two things:
- amplitude (negative and positive)
- vibration frequency
Is it possible to measure the negative amplitude with this board? The analog input of an arduino board use a 10bit ADC. So we have 1024 values available. Is it possible to use the value 0-511 for negative measurement and 512-1023 for positive? Normally I would use a voltage devider to set an offset to the negative sensor values. But in this case I don't know how the board is handling negativ sensor values.
Here is the board circuit:
For frequency measurement I want use the amplitude values and do a FFT.
is there any chance to get the negative values?