Microphone MAX4466, detect/distinguish sound levels.
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Microphone MAX4466, detect/distinguish sound levels.

by nardev on Thu Feb 21, 2013 4:58 pm

I expected it would be straight forward, just read analog pin and that is it.

Unfortunately, it constantly returns values around 300-330 or 500-550 (depending what Vcc i choose.)

Please, give me some tips. I just want to be able to detect some sound peeks.

For example, if average sound is represented with value around 100, i want that when i clap, it jumps so that it stands out a bit and that i can detect it.

Please, is it possible with MAX4466 and with no additional parts and how?
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Re: Microphone MAX4466, detect/distinguish sound levels.

by adafruit_support_bill on Thu Feb 21, 2013 9:17 pm

Because you are measuring a complex waveform, you need to integrate the signal over time. This is covered in the tutorial http://learn.adafruit.com/adafruit-micr ... r-breakout
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Re: Microphone MAX4466, detect/distinguish sound levels.

by nardev on Fri Feb 22, 2013 1:54 am

Ok, thank you.
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Re: Microphone MAX4466, detect/distinguish sound levels.

by Howard on Mon Mar 18, 2013 12:37 pm

I fed in a sound tone from my tablet and looked at output with scope and the signal level at 500 Hz was about 1/10 of the signal at 5000 Hz. Shouldn't
it be flat from 20 Hz to 20KHz?
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Re: Microphone MAX4466, detect/distinguish sound levels.

by adafruit_support_mike on Tue Mar 19, 2013 2:31 pm

Howard wrote:I fed in a sound tone from my tablet and looked at output with scope and the signal level at 500 Hz was about 1/10 of the signal at 5000 Hz. Shouldn't it be flat from 20 Hz to 20KHz?

The datasheets for the electret mic (http://www.adafruit.com/datasheets/CMA-4544PF-W.pdf) and the MAX4466 amplifier (http://www.adafruit.com/datasheets/MAX4465-MAX4469.pdf) both show reasonably flat response between 500Hz and 5kHz. Are you sure you aren't getting any signal attenuation from your tablet? An equalizer or treble boost effect would play with the signals coming out of the speakers.
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Re: Microphone MAX4466, detect/distinguish sound levels.

by TELINT on Thu Jun 05, 2014 7:59 am

I just bought the MAX4465 with electret microphone.
I would like to model this circuit in LTSPice. Can someone send me the schematic on this PCB in PDF format?
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Re: Microphone MAX4466, detect/distinguish sound levels.

by adafruit_support_bill on Thu Jun 05, 2014 9:05 am

The schematics are posted in the tutorial: https://learn.adafruit.com/adafruit-mic ... /downloads
If you click on it, there will be a selection of resolutions to choose from. The original size will have the best detail.
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Re: Microphone MAX4466, detect/distinguish sound levels.

by TELINT on Fri Jun 06, 2014 10:35 am

Thanks, I see you're schematic resembles the app note in data sheet, so I have a few questions.
1) For R5 and C4, I see you kept the same time constant, but lowered the resistance and raised the capacitance. Was there an advantage to doing this? Just want to learn form you're experience.
2) I like the ferrite beads isolating Analog from Digital, can you advise the part number of ferrite beads you're using?
That's all I need and should wrap up my questioning, thanks in advance.
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Re: Microphone MAX4466, detect/distinguish sound levels.

by adafruit2 on Fri Jun 06, 2014 1:03 pm

1) we tried to use stock parts we have here at adafruit, and also it increased the gain (from what we recall, it was a gain thing)
2) we use 300 ohm generic ferrite beads, 0805 - whatever Digikey has in stock that's low cost :)
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