db meter calibration issue using Grove Sound Sensor

hozzi.fozzi's picture

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Joined: Jan 04, 2019

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db meter calibration issue using Grove Sound Sensor
January 4, 2019 - 4:49pm

Hi,

I'm tried to create the dB meter project (https://circuitdigest.com/microcontroller-projects/arduino-sound-level-m...) with a different type of microphone from  Seeedstudio: http://wiki.seeedstudio.com/Grove-Sound_Sensor/ but I have huge variation in ADC values each time I disconnect/reconnect the microphone. Has anyone used  Grove-Sound_Sensor  with this project? 

It seems to be impossible to get a constant ADC value (bias) when no sound (i.e. silence, sound sensor covered to protect from ambient noise): At first connection I get ADV values around ~250 at silent and when disconnect and re-conecting the sensor again the 'silent' level is f.e. ~100 only. In other words there is an important  drift in the 'silent level'. Consequentlty the offset values at 40, 50, 60 dB calibration sound are drifting as well. I wonder if the Grove-Sound_Sensor (and the amplifier circuit on its PCB) is OK to realize this project?

Thanks in advance for your advice! Kind regards!

John_Kripto's picture

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Joined: Aug 11, 2018

Replies: 29
Sensor might be faulty
January 7, 2019 - 11:49am

Hi,

 I get ADV values around ~250 at silent and when disconnect and re-conecting the sensor again the 'silent' level is f.e. ~100 only.

This should not happen. I have used the same sensor earlier and my changes were like give or take 10. I think your sensor is faulty or damaged. It is also okay to use some local cheap sensor modules as there is not difference in the circuit.

The module is just a microphone with an amplifier.