I have a linear resonant actuator like this one:
https://www.gearbest.com/other-accessories/pp_670798.html
I need to control its frequency of vibration and for that I intend to use a potentiometer and an arduino to control de supply voltage and hence vary the frequency of vibration. But first of all I need to know how to measure the frequency so that I can adapt it to my purpose.
I am thinking of attaching a piezo sensor to the motor and with the arduino determine the period and hence the frequency of the signal produced when the piezo vibrates alongside with the LRA. Therefore I have some questions:
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Is my idea possible or is it nonsense?
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Can you please tell me if the tension produced when the piezo vibrates is sinusoidal and if so is the frequency proportional to the frequency of vibration of the motor?
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I need to reduce the tension produced to the levels of the arduino functioning tension but if I use a resistor of 1M Ohm will not that function as a filter and affect the signal?
Best Answer
It is possible but not necessary.
The best way is to drive like a MEMS or Xtal resonator which uses EMF current sensing to drive at resonant frequency. TI's solution is the DRV2605. It comes with other features to reduce energy consumption, and fast start stop etc.
http://www.ti.com/general/docs/lit/getliterature.tsp?baseLiteratureNumber=sloa188&fileType=pdf