#define TRIG_PIN 5
#define ECHO_PIN 18
#define BUZZER_PIN 2

void setup() {
  pinMode(TRIG_PIN, OUTPUT);
  pinMode(ECHO_PIN, INPUT);
  pinMode(BUZZER_PIN, OUTPUT);
  Serial.begin(115200);
}

void loop() {
  // Mengirim sinyal trigger
  digitalWrite(TRIG_PIN, LOW);
  delayMicroseconds(2);
  digitalWrite(TRIG_PIN, HIGH);
  delayMicroseconds(10);
  digitalWrite(TRIG_PIN, LOW);

  // Membaca sinyal echo
  long duration = pulseIn(ECHO_PIN, HIGH);
  int distance = duration * 0.034 / 2;  // Konversi waktu ke jarak (cm)
  
  Serial.print("Jarak: ");
  Serial.print(distance);
  Serial.println(" cm");

  // Jika jarak kurang dari 20 cm, nyalakan buzzer
  if (distance < 100) {
    digitalWrite(BUZZER_PIN, HIGH);  // Buzzer ON
  } else {
    digitalWrite(BUZZER_PIN, LOW);   // Buzzer OFF
  }

  delay(500);  // Tunggu 500ms sebelum pengukuran berikutnya
}