const int led1 = 15; 
const int led2 = 2; 
const int led3 = 4; 
const int trigPin = 5; 
const int echoPin = 18; 

void setup() {
  pinMode(led1, OUTPUT); 
  pinMode(led2, OUTPUT); 
  pinMode(led3, OUTPUT); 

  pinMode(trigPin, OUTPUT); 
  pinMode(echoPin, INPUT);  
  Serial.begin(9600);      
}

void loop() {
  digitalWrite(trigPin, LOW); 
  delayMicroseconds(2);       
  digitalWrite(trigPin, HIGH); 
  delayMicroseconds(10);      
  digitalWrite(trigPin, LOW); 

  long duration = pulseIn(echoPin, HIGH);
  float distance = (duration / 2.0) * 0.0344; 

  // Menampilkan jarak di Serial Monitor
  Serial.print("Jarak: ");
  Serial.print(distance);
  Serial.println(" cm");

  // Mengatur LED sesuai dengan jarak yang diukur
  if (distance < 120) {       // if distance is less than 120 cm
    digitalWrite(led1, HIGH); // turn on led1
    digitalWrite(led2, LOW);  
    digitalWrite(led3, LOW);  
  } else if (distance >= 120 && distance < 320) { 
    // if distance is in between 120 cm and 320 cm
    digitalWrite(led1, LOW); 
    digitalWrite(led2, HIGH); // turn on led2
    digitalWrite(led3, LOW); 
  } else {                    // Jika jarak lebih dari 320 cm
    digitalWrite(led1, LOW);  
    digitalWrite(led2, LOW);  
    digitalWrite(led3, HIGH); // turn on led3
  }
  delay(500); 
}