microphone not working on Orange Pi Zero

[peter12]

Hello,

I made my microphone setup with microphone mce103 according to this scheme 

pin 10 (MIC-BIAS) ..... 3 - 15V in scheme, 
pin 11 (MIC 1P) ....... NF, 
pin 12 (MIC 1N) ....... (-)

 

in alsamixer I have: audiocodec, mic1_2 audio capture mode.

then I tried: arecord -i -f S16 -r 22050 test.wav

and it saved this wav file (in attachment). I am not able to record audio, it records just noise as in attached sample.

 

What can be wrong please?

test_.wav

[Ford Prefect]

Hi

There seems to be a ground connection missing

here is the schematic from OrangePI PC

[peter12]

Thank you for your message. Please where can I found values for capacitors (C118,C120,C119,C121,C122) and resistors? Some of them they have values and some don't have.

And what is that green part between MIC1P and MIC1N?

I am sorry for newbie questions.
 

[zador.blood.stained]

4 minutes ago, peter12 said:

Thank you for your message. Please where can I found values for capacitors (C118,C120,C119,C121,C122) and resistors? Some of them they have values and some don't have.

 

All of them have their values on the schematics, you can use any online SMD value calculator to convert numbers like 101 and 104 to their values (100pF and 100nF respectively)

 

8 minutes ago, peter12 said:

And what is that green part between MIC1P and MIC1N?

 

Looks like a symbol for shielding. The key is that this circuit should be protected from EMI as much as possible.

[Ford Prefect]

The last number indicates the number of zeroes to add to get the value in picofarads so:

101 means 100 pF

104 means 0.1µF or 100000 pF

[zador.blood.stained]

4 minutes ago, Ford Prefect said:

The last number indicates the number of zeroes to add to get the value in picofarads

 

Or for a 3 digit number XYZ the value is XY * 10^Z

[peter12]

Thank you friends! I made small progress. Now I am able to record voice, but is is extremely quiet (I need to set maximum volume on my pc and VLC volume boost up to 200% - and even with these steps recorded voice is very quiet). Any idea please how to boost it? 

I tried to maximize everything in alsamixer but it did not help.

[pzw]

Which diagram are you using at the moment?

Are you sure the Mic is correctly connected? (+ and -)

[peter12]

thanks for help! I bought another microphone and I found out that first microphone was very low quality. Now everything works!

P.S. I am using scheme by Ford Prefect.

[Jakub Štajner]

Hi, nice topic and very useful informations
Pls, did somebody tried MEMS microphone on it? Thanks.