#include <Arduino.h>

#define TRIG_PIN 13
#define ECHO_PIN 12
#define RELAY_PIN 14
#define BUZZER_PIN 27

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

void loop() {
  long duration, distance;

  // Mengatur Trigger
  digitalWrite(TRIG_PIN, LOW);
  delayMicroseconds(2);
  digitalWrite(TRIG_PIN, HIGH);
  delayMicroseconds(10);
  digitalWrite(TRIG_PIN, LOW);

  // Menghitung durasi
  duration = pulseIn(ECHO_PIN, HIGH);
  
  // Menghitung jarak (cm)
  distance = (duration * 0.034 / 2);

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

  if (distance <= 50) {
    digitalWrite(RELAY_PIN, HIGH); // Nyalakan relay
    digitalWrite(BUZZER_PIN, HIGH); // Nyalakan buzzer
    tone(BUZZER_PIN, 500); //membunyikan buzzer sebesar 200Hz, boleh diubah-ubah sesuai dengan keinginan, semakin tinggi frekuensi semakin tinggi pula suara buzzernya

  } else {
    digitalWrite(RELAY_PIN, LOW); // Matikan relay
    digitalWrite(BUZZER_PIN, LOW); // Matikan buzzer
     tone(BUZZER_PIN, 0); 
  }

  delay(500); // Delay sebelum pembacaan berikutnya
}