#define  servoPin 3
#define  ultraPin 2
#define buzzerPin 5

#include <Servo.h>

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

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

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

void setup() {
  // put your setup code here, to run once:
  pinMode(ultraPin, OUTPUT);
  pinMode(servoPin, INPUT);
  Serial.begin(115200);
  pinMode(buzzerPin, OUTPUT);
  myservo.attach(9);
  myservo.write(90);
}

void loop() {
  // put your main code here, to run repeatedly:
 tutupPalang();
 interval +=100;
 if(interval>1000) interval = 0;
}

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

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

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