Hello everyone,
i tried to read frequency with max4466 microphone and store the value on sd card. But the SD card is connected on SCL pin (3 on micro) and my microphone max4466 also. Is it possible to identify these two sensors separately in order to get the max4466 frequency and after store the value on sd card ?
Thank you
No. If they are wired as you describe, which sounds unlikely.
However, please say what kind of Arduino is it?
Can you post a link to your microphone board?
Can you post a schematic of how you wired up your whole circuit?
Then we can see if there is an alternative way round this problem.
Thank you for your answer.
I use an arduino pro micro 5v.
My microphone is a max4466 like that : Electret Microphone Amplifier - MAX4466 with Adjustable Gain : ID 1063 : $6.95 : Adafruit Industries, Unique & fun DIY electronics and kits.
I dont have a drawing of my circuit sorry.
Maybe i can get the raw value of my microphone on analogic pin (A0 on my arduino for exemple) and make Fourier Transform to convert this raw signal in frequency ? I'm not very familiar with FFT on arduino.
I think you'll have to... the MAX4466 is analog.
FFT is not required to record digital audio. You just have to sample at a known-sample-rate and play-back at that same rate (and you might need to be aware of aliasing).
The Audacity Website has a quick tutorial about how audio is digitized (not Arduino related).
If you need frequency information you'll need FFT in any case.
The audio samples will be biased because the Arduino can't read negative voltages (and the microphone-board manufacturer's know this) i.e. Silence should read about 512 on a 10-bit ADC.
Depending on what you are doing you may want to subtract-out the bias in software. FFT automatically separates the DC bias (zero Hz) so you can just ignore the zero-Hz bin.
Thank you very much for your answer. So I will try to program the microphone with analogic pin. I need to record frequency values for a few seconds. This is to record the frequencies that the bees emit. I saw that there are arduino libraries for FFT, I will try to make them work.
OK it is not called " analogic pin." it is an analogue pin.
The signal it puts out is biased, so that means the no sound level will give a reading around 512, with loud noises producing anything between 0 to 1023. It says so in that link from Adafruit.
The audio waveform will come out of the OUT pin. The output will have a DC bias of VCC/2 so when it's perfectly quiet, the voltage will be a steady VCC/2 volt (it is DC coupled). If the audio equipment you're using requires AC coupled audio, place a 100uF capacitor between the output pin and the input of your device. If you're connecting to an audio amplifier that has differential inputs or includes decoupling capacitors,
So what was all the stuff about connecting it to SCL pin3?
If you don't have a circuit then how do you expect to make it?
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