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Mechanical resonant frequency of an ADXL345?

Question asked by cydrollinger on Jan 18, 2013
Latest reply on Apr 27, 2016 by Anthony.DeSimone

I am inquiring about the mechanical resonant frequency of the mass spring associated with the measuring mechanism of the ADXL345? I have made a measurement with an ADXL345 on a vertical mass spring with the electronics of the ADXL345 representing the mass atop of a pole. The pole is 1/4" fully threaded steel rod fixed in a vice 33"  below the top where the electronics are fixed. I pull the rod 5" off the center and let it go measuring the accelerations. I expected a largely under-damped 2nd order system mapping a single decaying resonant frequency decaying over a long time. Instead, the mapped accelerations indicate another frequency at the largest accelerations, letting go, and decaying to a single frequency, what I expected. I am wondering if I am measuring the beating frequencies of two mass springs, the system under test, and the ADXL345.

What is the mechanical resonant frequency of the ADXL345?

 

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Sincerely,

 

Cy Drollinger

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