#define led 13
#define trig 9
#define echo 8
#include <Servo.h>
#define buzzer 2
#include <LiquidCrystal_I2C.h>
LiquidCrystal_I2C lcd(0x27, 20, 4);

Servo myservo;

void setup() {
lcd.begin(20 ,4);
Serial.begin(9600);
Serial.println("palang kereta");

pinMode(led, OUTPUT);
pinMode(trig, OUTPUT);
pinMode(echo, INPUT);

myservo.attach(11);

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

  }


void loop() {
 
 float distance = readDistanceCM();
  Serial.print("Jarak = ");
  Serial.print(readDistanceCM());
  Serial.println(" cm");
 lcd.setCursor(0,0);
 lcd.print("jarak kereta:");
 lcd.setCursor(0,1);
 lcd.print(distance);
 lcd.setCursor(7,1);
 lcd.print("cm");

  if (distance <75){
    myservo.write(180);

    digitalWrite(led, HIGH);
    tone(buzzer, 500);
    delay(210);
    noTone(buzzer);
    digitalWrite(led, LOW);
    delay(210);
  }

else{

  myservo.write(0);
  noTone(buzzer);
  digitalWrite(led, LOW);
}
 }