//define variables
#define trigerPin 12
#define echoPin 13
#define ledPin 2
#define speakerPin 10
#define pitch 262

double duration,distance;                                                                                        

void setup() {
  //setup for Sensor
  Serial.begin(9600);
  pinMode(trigerPin,OUTPUT);
  pinMode(echoPin,INPUT);

  //setup for LED
  pinMode(ledPin,OUTPUT);

  //setup for Speaker
  pinMode(speakerPin,OUTPUT);

}

void loop() {
  //looping sensor (Create sound wave)
  digitalWrite(trigerPin,LOW);
  delayMicroseconds(2);
  digitalWrite(trigerPin,HIGH);
  delayMicroseconds(10);
  digitalWrite(trigerPin,LOW);
  delayMicroseconds(2);

  //get duration
  duration=pulseIn(echoPin,HIGH);

  //calculate distance
  distance=(duration/2)*0.0343;

  //consider maximum width of the door=200 cm

  if(distance<197){
    digitalWrite(ledPin,HIGH);
    tone(speakerPin,pitch);
    delay(197);

    digitalWrite(ledPin,LOW);
    noTone(speakerPin);
    delay(197);
  }
  else{
    digitalWrite(ledPin,LOW);
    noTone(speakerPin);
  }

}