const int buzzerPin = 27; // Pin buzzer
const int trigPin = 5;    // Pin trigger ultrasonik
const int echoPin = 18;   // Pin echo ultrasonik
const int redLedPin = 25; // Pin LED merah
const int greenLedPin = 26; // Pin LED hijau
const int servoPin = 15;  // Pin servo

// Define sound speed in cm/uS
#define SOUND_SPEED 0.034
#define CM_TO_INCH 0.393701

long duration;
float distanceCm;
float distanceInch;

void setup() {
  Serial.begin(115200);
  pinMode(buzzerPin, OUTPUT);
  pinMode(trigPin, OUTPUT);
  pinMode(echoPin, INPUT);
  pinMode(redLedPin, OUTPUT);
  pinMode(greenLedPin, OUTPUT);
  pinMode(servoPin, OUTPUT);
}

void loop() {
  digitalWrite(trigPin, LOW);
  delayMicroseconds(2);
  digitalWrite(trigPin, HIGH);
  delayMicroseconds(10);
  digitalWrite(trigPin, LOW);

  duration = pulseIn(echoPin, HIGH);
  distanceCm = duration * SOUND_SPEED / 2;
  distanceInch = distanceCm * CM_TO_INCH;

  if (distanceCm < 200) {
    // Jika jarak kurang dari 200 cm, bunyikan buzzer
    buzzBuzzer();
    digitalWrite(redLedPin, LOW);
    digitalWrite(greenLedPin, HIGH);
    digitalWrite(servoPin, HIGH); // Set servo ke posisi 90 derajat
  } else {
    // Jika jarak lebih dari 200 cm, matikan bunyi buzzer dan kembalikan servo ke posisi awal
    digitalWrite(buzzerPin, LOW);
    digitalWrite(redLedPin, HIGH);
    digitalWrite(greenLedPin, LOW);
    digitalWrite(servoPin, LOW); // Set servo ke posisi 0 derajat
  }

  Serial.print("Distance (cm): ");
  Serial.println(distanceCm);
  Serial.print("Distance (inch): ");
  Serial.println(distanceInch);
  
  delay(1000);
}

// Fungsi untuk membuat bunyi pada buzzer
void buzzBuzzer() {
  digitalWrite(buzzerPin, HIGH); // Hidupkan buzzer
  delay(3000); // Tahan bunyi selama 3 detik
  digitalWrite(buzzerPin, LOW); // Matikan buzzer
}