#include <Servo.h> 

#define TRIGGER_PIN 2 
#define ECHO_PIN 3 
#define SERVO_PIN 9 

Servo myServo; 

void setup() { 
  pinMode(TRIGGER_PIN, OUTPUT); 
  pinMode(ECHO_PIN, INPUT); 

  myServo.attach(SERVO_PIN); 
}

void loop() { 
  long duration, distance; 
 
  // Kirim sinyal ultrasonik 
  digitalWrite(TRIGGER_PIN, LOW); 
  delayMicroseconds(2); 
  digitalWrite(TRIGGER_PIN, HIGH); 
  delayMicroseconds(10); 
  digitalWrite(TRIGGER_PIN, LOW); 
 
  // Baca waktu pantulan ultrasonik 
  duration = pulseIn(ECHO_PIN, HIGH); 
 
  // Hitung jarak dalam centimeter 
  distance = (duration / 2) / 29.1; 
 
  // Jika objek berada dalam jarak 20 cm, putar servo motor ke posisi 90 derajat 
  if (distance <= 150) { 
    myServo.write(90); 
  } else { 
    // Jika tidak, putar servo motor ke posisi 0 derajat 
    myServo.write(0); 
  } 
 
  delay(500); 
}