ESP 32 with mems MIC SPW2430

Manveen
Posts: 5
Joined: Wed Jun 13, 2018 10:11 am

ESP 32 with mems MIC SPW2430

Postby Manveen » Thu Sep 06, 2018 8:27 am

Hi all,
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 :https://www.knowles.com/docs/default-so ... hr5h-b.pdf

Right now I using the Adafruit SPW2430 mems mic breakout board for testing purpose
product site here :https://www.adafruit.com/product/2716

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 esp 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

Code: Select all

#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
}

Attachments
IMG_20180906_180832.jpg
GREEN PROBE IS DSO AND RED PROBE IS FOR DMM
IMG_20180906_180832.jpg (837.97 KiB) Viewed 5266 times
BREAKOUT BOARD SCHEMATIC.png
BREAKOUT BOARD SCHEMATIC
BREAKOUT BOARD SCHEMATIC.png (18.48 KiB) Viewed 5266 times
mems ckt.png
CIRCUIT SCHEMATIC
mems ckt.png (8.03 KiB) Viewed 5266 times

Manveen
Posts: 5
Joined: Wed Jun 13, 2018 10:11 am

Re: ESP 32 with mems MIC SPW2430

Postby Manveen » Sun Sep 09, 2018 5:43 am

For anyone who is interested I have found the answer
https://forums.adafruit.com/viewtopic.php?f=8&t=140676


TLDR :

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

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