void setup(){
  Serial.begin(9600);
  pinMode(13,OUTPUT);
  pinMode(12,OUTPUT);
  pinMode(14,OUTPUT);
  pinMode(4,OUTPUT);
  pinMode(15,OUTPUT);
  pinMode(2,INPUT);
}

void loop(){
  digitalWrite(15,LOW);
  delayMicroseconds(2);
  digitalWrite(15,HIGH);
  delayMicroseconds(10);
  digitalWrite(15,LOW);
  int duration=pulseIn(2,HIGH);
  float distance=duration*0.034/2;

  Serial.println("Jarak : " + String(distance,2) + " cm");

  if(distance<=50){
    digitalWrite(13,LOW);
    digitalWrite(12,LOW);
    digitalWrite(14,LOW);
    noTone(4);
  }
  else if((distance>50) && (distance<=100)){
    digitalWrite(13,HIGH);
    digitalWrite(12,LOW);
    digitalWrite(14,LOW);
    noTone(4);
  }
  else if((distance>100) && (distance<=150)){
    digitalWrite(13,LOW);
    digitalWrite(12,HIGH);
    digitalWrite(14,LOW);
    noTone(4);
  }
  else if((distance>150) && (distance<=300)){
    digitalWrite(13,LOW);
    digitalWrite(12,LOW);
    digitalWrite(14,HIGH);
    noTone(4);
  }
  else if(distance>300) {
    digitalWrite(13,HIGH);
    digitalWrite(12,HIGH);
    digitalWrite(14,HIGH);
    tone(4,200);
  }
  delay(200);
}