#define TRIG_PIN 9
#define ECHO_PIN 8
#define LED_PIN 7
#define BUZZER_PIN 6

long duration;
int distance;

void setup() {
  pinMode(TRIG_PIN, OUTPUT);
  pinMode(ECHO_PIN, INPUT);
  pinMode(LED_PIN, OUTPUT);
  pinMode(BUZZER_PIN, OUTPUT);
  Serial.begin(9600);
  Serial.println("Sensor Pendeteksi Gerakan Aktif...");
}

void loop() {
  // Kirim pulsa trigger ke sensor
  digitalWrite(TRIG_PIN, LOW);
  delayMicroseconds(2);
  digitalWrite(TRIG_PIN, HIGH);
  delayMicroseconds(10);
  digitalWrite(TRIG_PIN, LOW);

  // Hitung durasi pantulan echo
  duration = pulseIn(ECHO_PIN, HIGH);

  // Konversi ke jarak (cm)
  distance = duration * 0.034 / 2;

  Serial.print("Jarak: ");
  Serial.print(distance);
  Serial.println(" cm");

  // Jika ada objek dalam jarak < 20 cm
  if (distance > 0 && distance < 300) {
    digitalWrite(LED_PIN, HIGH);
    tone(BUZZER_PIN, 1000); // buzzer bunyi
    delay(200);
    digitalWrite(LED_PIN, LOW);
    noTone(BUZZER_PIN);     // buzzer mati
    delay(200);
  } 
  else {
    digitalWrite(LED_PIN, LOW);
    noTone(BUZZER_PIN);
  }

  delay(100);
}