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Topic: Voice recorder: can't create a clear wave file (Read 892 times) previous topic - next topic

MarkT

Hmm, interesting, that layout seems pretty good, no ground loop, I guess the 5V rail may be dipping?
I presume the SDcard breakout you have has its own 3.3V regulator?

Yes, try 100uF or more across the supply on the SDcard module itself (decoupling is capacitance,
electrolytic provides bulk values of capacitance rather than dealing with very fast transients, and
is usually what makes a difference to audio.

Also you might want to try adding about 10 to 20 ohms in line with the 5V supply to the microphone
module and add electrolytic decoupling there too.
[ I will NOT respond to personal messages, I WILL delete them, use the forum please ]

Azeez_Jimoh

The SD card breakout uses 5v it doesnt work on 3.3v

I will have to go get the capacitor and resistor and try what u suggest over here..

when am done i will let u know the output.


Hillcres-Hellio

Hi MarkT,

I'm not sure being clear with the terms: When you say "across" the supply of the SD reader, it means between 3.3V and Ground?

And "in line" means on the 3.3V line wich goes into the mic right?

Otherwise, great news: i made it work once with my arduino UNO. I changed some wires and re-started everything at the beggining, on a breadboard (before, everything was soldered)

But now i try to make it work on a Feather from adafruit and the same old problem comes again, idk why...

Azeez, if you're hearing me, try to do like i did, and also to use two different breadboards for the mic and the sd card reader. It might be a dumb problem like this.

MarkT

#18
Oct 19, 2018, 03:24 pm Last Edit: Oct 19, 2018, 03:25 pm by MarkT
Hi MarkT,

I'm not sure being clear with the terms: When you say "across" the supply of the SD reader, it means between 3.3V and Ground?
yes
Quote
And "in line" means on the 3.3V line wich goes into the mic right?
yes
Quote
Otherwise, great news: i made it work once with my arduino UNO. I changed some wires and re-started everything at the beggining, on a breadboard (before, everything was soldered)

But now i try to make it work on a Feather from adafruit and the same old problem comes again, idk why...

Azeez, if you're hearing me, try to do like i did, and also to use two different breadboards for the mic and the sd card reader. It might be a dumb problem like this.
Do you have a ground loop?  That's not going to work with microphone-level signals, must have star-grounds.
[ I will NOT respond to personal messages, I WILL delete them, use the forum please ]

Hillcres-Hellio

Do you have a ground loop?  That's not going to work with microphone-level signals, must have star-grounds.
As on the Uno, there are different ground pins on the Feather 32u4 and the global architecture is the same. You mean there is a star ground on Uno boards and not on Feathers?

Azeez_Jimoh

NO Hillcres the different board for different mic and SD card is not working

i havent tried the 100uF capacitor yet cause i have to go buy some but the two 20uF combined together (40uF) didnt do anything about the noise and also the resistors

zoomx

@Azeez_Jimoh,
power source is a common noise source if taken fron a PC USB.

I believe that maybe also the SD can be a problem when it writes effectively on flash, but this depends strongly on SD.

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