Yell back

int Br=1 ;
int yell =8;

void setup() {
  // put your setup code here, to run once:
  pinMode(yell,OUTPUT);
Serial.begin(9600);

}

void loop(){int val;
      val=analogRead(0);   //connect mic sensor to Analog 0
      Serial.print("Sound=");
      Serial.println(val,DEC);
      
     
      if(val>=540)
      {
        digitalWrite(yell, HIGH);
      }
      else
      {
        digitalWrite(yell, LOW);
      }
      delay(100);
}