const int triggerPin = 8;
const int echoPin = 9;
const int LED1_PIN = 2;
const int LED2_PIN = 4;
const int LED3_PIN = 7;

long durasi;
int jarak;

void setup() {
pinMode(triggerPin, OUTPUT); 
pinMode(LED1_PIN, OUTPUT); 
pinMode(LED2_PIN, OUTPUT); 
pinMode(LED3_PIN, OUTPUT); 
pinMode(echoPin, INPUT);
  
Serial.begin(9600); 
}

void loop() {
  digitalWrite(triggerPin, LOW);
  delayMicroseconds(2);
  digitalWrite(triggerPin, HIGH);
  delayMicroseconds(10);
  digitalWrite(triggerPin, LOW);
  durasi = pulseIn(echoPin, HIGH);
  jarak = durasi * 0.034/2;
  

  if (jarak > 30) {
    digitalWrite(LED1_PIN, HIGH);
    digitalWrite(LED2_PIN, LOW);
    digitalWrite(LED3_PIN, LOW);
  } else if (jarak <= 30 && jarak > 20) {
    digitalWrite(LED1_PIN, LOW);
    digitalWrite(LED2_PIN, HIGH);
    digitalWrite(LED3_PIN, LOW);
  } else {
    digitalWrite(LED1_PIN, LOW);
    digitalWrite(LED2_PIN, LOW);
    digitalWrite(LED3_PIN, HIGH);
  }
  
  // Menampilkan jarak pada Serial Monitor
  Serial.print("Jarak: ");
  Serial.print(jarak);
  Serial.println("cm");
  
  // Menunggu selama 500 milidetik sebelum mengulangi loop
  delay(500);
}