SPW2430 MEMS MIC Taking time in returning to base Voltage

Question

BREAKOUT BOARD SCHEMATICCIRCUIT SCHEMATIC

Green probe is for DSO and red probe is for DMM

I am trying to create project using ESP 32 with arduino IDE which turns on when a snap is detected. I will be using using spw2430 mems mic datasheet here :Mems MIC Datasheet Right now I using the Adafruit SPW2430 mems mic breakout board for testing purpose product site here :https://www.adafruit.com/product/2716

100 to 10kHz frequency resp VPP= 200mV Dc bias= 700mV Zout=450 Ohm

The problem I am facing is whenever i snap my fingers or clap my hand the output voltage goes up (as expected) BUT it takes a 4-5 seconds to come back to normal reading . Ideally it should not take that much amount of time to come back to normal reading. It should take 10 ms to come back to normal readings.

I am polling every 500 microseconds and the attenuation of the ESP32 has been set to 0 db so that the REF voltage scale is in 0 - 1V. this similar problem is happening with arduino uno (with same set of test conditions) . The input of adc is connected to the DC pin of the Breakout Board. (Which does NOT have any capacitor in between the o/p of mic and I/p of adc.)

Here is the code I am using

#include<esp32-hal-adc.h>
#define ANALOG_PIN 4

void setup()
{

  pinMode(ANALOG_PIN,INPUT);
  Serial.begin(115200); 
  /*
   * typedef enum 
   {
    ADC_0db,      // 0 to 1 v 
    ADC_2_5db,  // 0 to 1.27 v
    ADC_6db,     // 0 to 1.75 v
    ADC_11db     // 0 to 3.3 v
   } adc_attenuation_t; // changes Ref Voltage Scale
   */

  analogSetPinAttenuation(ANALOG_PIN,ADC_0db);
 // Set the attenuation for particular pin currently 0-1 v

}

void loop() 
{
  int raw_value = 0; // to store raw value of mic

  raw_value = analogRead(ANALOG_PIN); // Reading the op voltage of mic

  Serial.print("Raw value is : ");
  Serial.println(raw_value);

  delayMicroseconds(500); // Sampling every 500 uSec
}

I also have a voltmeter. i connected one probe to GND and OTher one to DC pin output of MEMS Mic. The voltage reading is 700mV. When I snap my finger it reaches 800mV immediately But It takes 4-5 seconds to come back to 700mV

Answer 1

For anyone who is interested I have found the answer

anwser here

TLDR :

It is the mic's general behavior And no one can do anything about it