#define ECHO_PIN 2
#define TRIG_PIN 15
#define BUZZER 22

void setup() {
  Serial.begin(115200);
  //pinMode(LED_BUILTIN, OUTPUT);
  pinMode(TRIG_PIN, OUTPUT);
  pinMode(ECHO_PIN, INPUT);
  pinMode(5, OUTPUT);
  pinMode(18, OUTPUT);
  pinMode(19, OUTPUT);
  pinMode(21, OUTPUT);
}

void loop() {
  //untuk menghasilkan sinyal ultrasonic
  digitalWrite(TRIG_PIN, LOW);
  delayMicroseconds(2);
  digitalWrite(TRIG_PIN, HIGH);
  delayMicroseconds(10);
  digitalWrite(TRIG_PIN, LOW);

  //membaca sinyal ultrasonic
  int duration = pulseIn(ECHO_PIN, HIGH);
  float distance = duration * 0.034 / 2;

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

  if(distance > 50){
    digitalWrite(21, HIGH);
    digitalWrite(19, LOW);
    digitalWrite(18, LOW);
    digitalWrite(5, LOW);
    }
  if(distance > 100){
    digitalWrite(21, HIGH);
    digitalWrite(19, HIGH);
    digitalWrite(18, LOW);
    digitalWrite(5, LOW);
    }
  if(distance > 200){
    digitalWrite(21, HIGH);
    digitalWrite(19, HIGH);
    digitalWrite(18, HIGH);
    digitalWrite(5, LOW);
    }
  if(distance > 300){
    digitalWrite(21, HIGH);
    digitalWrite(19, HIGH);
    digitalWrite(18, HIGH);
    digitalWrite(5, HIGH);
    tone(BUZZER, 1000);

  } else {
    digitalWrite(21, LOW);
    digitalWrite(19, LOW);
    digitalWrite(18, LOW);
    digitalWrite(5, LOW);
    tone(BUZZER, LOW);

  }
}