KY-037 Microphone Sound Sensor with Arduino

//KY-037 Mic module

const int sensor_digital = 2;   //connected to DO on module
const int sensor_analog = A0;   //connected to AO on module

void setup() {
  
  pinMode(sensor_digital, INPUT);
  pinMode(sensor_analog, INPUT);
  Serial.begin(115200);
  
}

void loop() {
  
  int analog_value = analogRead(sensor_analog);
  int digital_value = digitalRead(sensor_digital);
  
  Serial.print("Analogue value = ");
  Serial.println(analog_value);

  if (digital_value == 0) {   //digital output is inverted
    Serial.println("Digital pin triggered");
  }

  delay(20);  //50Hz sample rate

}

This is a simple sketch reads the analogue values of the sound sensor module, and outputs the analogue value to the serial monitor.

The digital output is also monitored and will post a message to the serial monitor if it is triggered.

Without a way of creating a controlled sound to test, it’s not possible to give any solid advice. This graph shows what happens when you blow on the microphone at different analogue values.

There does seems to be a pattern in that the higher the analogue value, the lower the range of values and longer the duration – however, this wasn’t a controlled or repeated test, so could be a complete fluke.

Regardless of that, it shows what happens to the output and gives an indication of the type of interrupt trigger required; for example Test 1 would respond to a RISING trigger when a strong peak (greater than 512) is detected, whereas Test 3 would respond to a FALLING trigger (lower than 512). In all instances, a CHANGE trigger would respond to a strong signal.

Altering the code used within the “Wake an Arduino IR Receiver” page, it’s easy to set up the microphone and as the “alarm” to wake the Arduino as a lower powered listening device.

As previous this uses the LowPower.h library, and an interrupt.

Note this setup requires the digital output of the microphone connected to either pins D2 or D3 for a standard Arduino Uno/Nano (Any interrupt enabled pin).

If you’re using motors (or other large loads) in your circuit, then the voltage drop can cause a false trigger.

#include "LowPower.h"

const int mic_digital_pin = 2;

/////////////////////////////
void ISR_flag() {

}
//////////////////////////////////////////////
void setup() {
  Serial.begin(115200);
  
  attachInterrupt(digitalPinToInterrupt(mic_digital_pin), ISR_flag, CHANGE);
}
//////////////////////////////////////////////
void loop() {
  Serial.println("Time for sleep...");
  delay(200);
  LowPower.powerDown(SLEEP_FOREVER, ADC_OFF, BOD_OFF);
  Serial.println("...I'm awake now");
  delay(1000);
}