delay circuit, that triggers only when input has been zero for a while ...

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evsc

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i am using a piezo sensor to read in vibration values, and i want to trigger another action once the vibration has died down. it could be like a delay function that gets reset each time the vibration value reaches a certain value above zero, and only triggers if it hasn't been reset in a while ...

any idea on what would be a simple solution to implement that?

thanks.
 
yes, but wouldn't this one already be triggered during the sine-wave vibration coming from the piezo? As soon as the TRIGGER input pin goes low, the timer output goes high. The sensor will report AC signal from the piezo, and therefore hit 0V quite often ...
 
You need to rectify the AC signal with a diode to get a DC level. You can use a long RC time-constant filter to control the decay of the DC level when the signal goes away. Use that level to control the one-shot.
 
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