#define TRIG_PIN 18
#define ECHO_PIN 5
#define BUZZER_PIN 2
#define LED_PIN 4

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

float mesafeOlc() {
  digitalWrite(TRIG_PIN, LOW);
  delayMicroseconds(2);
  digitalWrite(TRIG_PIN, HIGH);
  delayMicroseconds(10);
  digitalWrite(TRIG_PIN, LOW);

  long sure = pulseIn(ECHO_PIN, HIGH);
  float mesafe = sure * 0.0343 / 2;
  return mesafe;
}

void loop() {
  float mesafe = mesafeOlc();
  Serial.print("Mesafe: ");
  Serial.print(mesafe);
  Serial.println(" cm");

  // Alarm mesafe sınırı
  if (mesafe > 0 && mesafe < 20) {
    int hiz = map(mesafe, 1, 20, 50, 500);  // Mesafe azaldıkça daha hızlı beep
    digitalWrite(BUZZER_PIN, HIGH);
    digitalWrite(LED_PIN, HIGH);
    delay(50);
    digitalWrite(BUZZER_PIN, LOW);
    digitalWrite(LED_PIN, LOW);
    delay(hiz);
  } 
  else {
    digitalWrite(BUZZER_PIN, LOW); // Ses kapalı
    digitalWrite(LED_PIN, LOW);
  }

  delay(50);
}