//deklarasikan pin input
#define ECHO_PIN 3
#define TRIG_PIN 2
#define pinBuzzer 5
#define input_pir 11

int pir_state=LOW;

//gunakan library servo
#include <Servo.h>

//buat variabel servo dalam hal ini jadi servoku
Servo servoku;

//posisi sudut servo di awal 0 
int potpin = 0;
int val;

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 setup () {
  pinMode(TRIG_PIN, OUTPUT);
  pinMode(ECHO_PIN, INPUT);
  pinMode(input_pir, INPUT);
  Serial.begin(115200);
  pinMode(pinBuzzer, OUTPUT);

//deklarasikan servo pada pin 9
  servoku.attach(9);
}

void loop() {
  float distance = readDistanceCM();
 //baca jarak 
   if(digitalRead(input_pir) == HIGH){
   if(distance <=201 && pir_state == LOW){
    Serial.println("KERETA API MENDEKAT, SEGERA TUTUP PALANG PINTU KERETA API!");
    Serial.println("distance(cm): " + String(distance));
    servoku.write(90);
    delay(15);
    tone(pinBuzzer, 1000);
    delay(200);
    tone(pinBuzzer, 500);
    delay(200);
    Serial.print("Ukur jarak:");
  Serial.println(readDistanceCM());
   }
   }
  else{
    servoku.write(0);
    noTone(pinBuzzer);
  }
//opsi lain untuk penutupan palang secara manual via potensiometer
  val = analogRead(potpin);
  val = map(val, 0, 1023, 0, 90);
  servoku.write(val);
  delay(15);
}