I want to detect the mechanical shock of a machine. To measure the vibrational shock I am using Minisense 100 Piezoelectric vibration sensor. I have done the feasibility test using it and it is giving output as expected. I have observed on the oscilloscope output frequency for all type vibrational intensity and I came in conclusion that I want to sense only range between 50Hz to 100 Hz. For this frequency range, I want to create a 3.3V digital logic to interface with a microcontroller digital pin.

I have designed a bandpass filter using LM358AN and a comparator. My circuit in below
I didn't get any output from it. Please let me know what's wrong in this circuit?

 

hi SM2,
Look at this link to compare the type of amplifier required.
https://scienceprog.com/thoughts-on-interfacing-piezo-vibration-sensor/
E

 

hi SM2,
Look at this link to compare the type of amplifier required.
https://scienceprog.com/thoughts-on-interfacing-piezo-vibration-sensor/
E

Thank you

 

Why is the input resistor to ground the extremely low resistance of only 3.3k when the video shows 3.3M (1000 times more)? But a lousy old LM358 opamp will not work properly with 3.3M. With a 3.3V supply its output high is only about +1.9V.

Also, the very simple bandpass filter has a droopy response with gradual slopes. The lowpass cuts most of its frequencies and the highpass also cuts most of its frequencies. Even mid frequencies of the bandpass are reduced a lot.

 

low power http://static.scbist.com/scb/uploaded/datasheets/UA776.pdf
perhaps https://www.egr.msu.edu/eceshop/Parts_Inventory/datasheets/lm4250cn.pdf (faster than previous)
or same what you got but more expensive
http://www.ti.com/product/LMV321 -- http://www.ti.com/lit/ds/symlink/lmv321.pdf