#include<Servo.h>
Servo servo;

const byte TRIG_PIN = 4;
const byte ECHO_PIN = 5;
const byte buzzer = 12;

byte derajat = 0;
long durasi, jarak = 0;

void setup() {
  Serial.begin(9600);
  pinMode(buzzer, OUTPUT);
  pinMode(TRIG_PIN, OUTPUT);
  pinMode(ECHO_PIN, INPUT);
  servo.attach(6);
  servo.write(0);
}

void loop() {
  for (derajat = 0; derajat < 180; derajat++) {
    servo.write(derajat);
    bacaUltrasonic();
    delay(500);
  }
  for (derajat = 180; derajat > 0; derajat--) {
    servo.write(derajat);
    bacaUltrasonic();
    delay(500);
  }
}

void bacaUltrasonic() {
  digitalWrite(TRIG_PIN, LOW);
  delayMicroseconds(2);
  digitalWrite(TRIG_PIN, HIGH);
  delayMicroseconds(10);
  digitalWrite(TRIG_PIN, LOW);

  durasi = pulseIn(ECHO_PIN, HIGH);
  jarak = durasi * 0.0344 / 2;

  Serial.print("Jarak: "); Serial.print(jarak);

  if (jarak < 25) {
    Serial.println(" cm - TERDETEKSI ADANYA OBJEK!!!");
    digitalWrite(buzzer, HIGH);
  }
  else {
    Serial.println(" cm - TIDAK ADA OBJEK!!!");
    digitalWrite(buzzer, LOW);
  }
}