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I have a piezo crystal (SEN-10293, datasheet: 7BB-20-6L0) that I am using to detect if a person sits on a chair. The compression of the crystal generates enough voltage to wake up a microcontroller from sleep. This is done by connecting the crystal to a relevant GPIO pin set to wake the microcontroller when it is set to high. The problem is, the piezo crystal seems to be too sensitive, it will generate enough voltage to wake the microcontroller even when a person just moves around a little on the chair. My question is then, is there some way to reduce the sensitivity of the piezo crystal? I was searching around and came across Passive High Pass filter circuits which allow you to filter out frequencies below a certain threshold, but would this work for a piezo crystal, I am not super familiar with how voltages and frequencies relate to each other. Secondly, when a person gets off the chair the piezo instead produces a negative voltage, is there some way to invert this so I can use this to also wake the microcontroller, or is that not feasible?

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  • \$\begingroup\$ Yes this can be done. Happy now? \$\endgroup\$ – user_1818839 Feb 24 at 13:57
  • \$\begingroup\$ Please get yourself a good book on basic electronics. Estimating your knowledge from what you write, an answer will be either not acceptable for you or too broad. \$\endgroup\$ – the busybee Feb 25 at 12:14

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