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Topic: Measure Sound Frequency with MAX3814 (Read 109 times) previous topic - next topic


May 16, 2017, 04:08 am Last Edit: May 16, 2017, 04:22 am by openmic
I've been having difficulty measuring the frequency of a sound (20hz - 20khz)coming from a MAX3814 microphone with auto-gain-control. The microphone's output pin produces 2vpp with a bias of 1.25v. Should I be able to use this voltage to find the sound's frequency without any other amplifiers? The voltage is already measurable, yeah? Why modify it?

All my internet research says I have to use digital pin #5 for its special timing properties. (Something about interrupts. I'm still learning)

Am I wrong to think I don't need to amplify the signal? (connecting the Vout of my mic directly to the Arduino)

I'm using FreqCounter in the code.

Any guidance or help appreciated. I attached an image of my circuit.https://drive.google.com/open?id=1CGSG5n7AHhMQetWMZaWVHlNAc9QA2PI8Qg


As far as I can tell, it looks like you need a digital signal (not analog music or a "normal" audio signal).   And, I assume it should be a square-wave or pulse of a single frequency.

The "preamplifier" circuit with a transistor may clip, creating an almost-square wave, with a ~1V line-level audio signal.  But, you probably would need a simple-pure audio tone.


Note that you can not measure the frequency of most real sounds this way. Sounds like a musical instrument are complex and always changing so their is no simple technique you can use.

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