#define ECHO_PIN 3
#define TRIG_PIN 2
#define pinBuzzer 5

#include <Servo.h>

Servo myservo;
int rotasi = 90;
int interval = 0;

float readDistanceCM() {
  digitalWrite(TRIG_PIN, LOW);
  delayMicroseconds(2);
  digitalWrite(TRIG_PIN, HIGH);
  delayMicroseconds(10);
  digitalWrite(TRIG_PIN, LOW);
  int duration = pulseIn(ECHO_PIN, HIGH);
  return duration * 0.034 / 2;
}

void soundBuzzer() {
  if (interval < 500) {
    tone(pinBuzzer, 250);
  } else if (interval > 500) {
    tone(pinBuzzer, 100, 800);
  }
}

void setup() {
  pinMode(TRIG_PIN, OUTPUT);
  pinMode(ECHO_PIN, INPUT);
  Serial.begin(115200);
  pinMode(pinBuzzer, OUTPUT);
  myservo.attach(9);
  myservo.write(90);
}

void loop() {
  tutupPalang();
  interval += 100;
  if (interval > 1000) interval = 0;

  // Display distance on serial monitor
  float distance = readDistanceCM();
  Serial.print("Distance: ");
  Serial.print(distance);
  Serial.println(" cm");
}

void tutupPalang() {
  float jarak = readDistanceCM();
  if (jarak > 0 && jarak < 100) {
    soundBuzzer();
    tutup();
  } else {
    buka();
    noTone(pinBuzzer);
  }
}

void tutup() {
  if (rotasi <= 90) {
    myservo.write(rotasi);
    delay(100);
    rotasi--;
  }
  if (rotasi <= 0) rotasi = 0;
}

void buka() {
  if (rotasi <= 90) {
    myservo.write(rotasi);
    delay(100);
    rotasi += 4;
  }
  if (rotasi >= 90) rotasi = 90;
}