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Here is a "stripped down version" of a sketch I used to replicate the Clap On, Clap Off lamp switch we had in the 1980's. It works with the KY-038 sound sensor module you currently have. You will need to install the VirtualDelay Library.

The sound sensor module is very sensitive. A quarter turn of the potentiometer around the "sweet spot" makes a huge difference. Too sensitive, and the digital output is constantly high. If it's not sensitive enough, then you have to physically "tap" the microphone to get a high/low transition out of it.

Please note: This sketch uses delay() which is "blocking code" and it's use is usually not recommended.

#include "avdweb_VirtualDelay.h"
byte clapCounter = 0;
const byte soundSensorPin = 2;
const unsigned long loopDelay = 1;
const unsigned long clapCounterDelay = 400;
unsigned long clapCounterTimerDuration = 1000;
unsigned long previousMillis = 0;

void setup(){
  pinMode(LED_BUILTIN, OUTPUT);
}

void loop(){

  // Timer object.
  static VirtualDelay clapCounterTimer;

  // Get the current time.
  unsigned long currentMillis = millis();

  // Check for a clapping sound (1 ms works good). If too much time
  // elapses here, you could miss the "beginning" of the clap.
  if(myTimer1(loopDelay, currentMillis) == 1){

    // Clap detected.
    if(digitalRead(soundSensorPin) == 1){

      clapCounter += 1;

      // When the first the clap is detected, start a timer
      // to reset the clap counter to 0 after 1 second.
      if(clapCounter == 1){
        clapCounterTimer.start(clapCounterTimerDuration);
      }

      // Delay execution of the loop. 400 ms works good.
      delay(clapCounterDelay);

      // If a second clap is detected, toggle the LED ON/OFF.
      if(clapCounter > 1){
        digitalWrite(LED_BUILTIN, !digitalRead(LED_BUILTIN));
      }

    }
  }

  // Reset the clap counter to 0 after 1 second. If
  // you don't do this, you could clap once, wait a
  // minute, then clap again and the LED will change state.
  if(clapCounterTimer.elapsed()){
    clapCounter = 0;
  }

}

// Clap loop timer.
byte myTimer1(unsigned long loopDelay, unsigned long currentMillis){
  if(currentMillis - previousMillis >= loopDelay){previousMillis += loopDelay;return 1;}
  else{return 0;}
}