#define TRIG_PIN 12
#define ECHO_PIN 14
#define MQ2_PIN 34
#define BUZZER_PIN 25

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

void loop() {
  // Baca jarak dari sensor HCSR04
  digitalWrite(TRIG_PIN, LOW);
  delayMicroseconds(2);
  digitalWrite(TRIG_PIN, HIGH);
  delayMicroseconds(10);
  digitalWrite(TRIG_PIN, LOW);
  long duration = pulseIn(ECHO_PIN, HIGH);
  float distance = duration * 0.034 / 2;

  // Baca nilai gas dari sensor MQ2
  int gasValue = analogRead(MQ2_PIN);

  // Jika jarak terlalu dekat atau gas tinggi, buzzer bunyi
  if (distance < 20 || gasValue > 500) {
    digitalWrite(BUZZER_PIN, HIGH);
    tone(BUZZER_PIN, 1000);
  } else {
    digitalWrite(BUZZER_PIN, LOW);
  }

  // Debugging ke Serial Monitor
  Serial.print("Jarak: "); Serial.print(distance); Serial.print(" cm, ");
  Serial.print("Gas: "); Serial.println(gasValue);

  delay(500);
}