#include <Servo.h> //library

#define trig 5
#define echo 4
#define buzzer 8

Servo myservo; //jenis servo

void setup() {
  // put your setup code here, to run once:
Serial.begin(115200);
myservo.attach(6); //pin servo
pinMode(buzzer, OUTPUT);
pinMode(trig, OUTPUT);
pinMode(echo, INPUT);
}

float readDistanceCM(){
  
  digitalWrite(trig, LOW);
  delayMicroseconds(2);
  digitalWrite(trig, HIGH);
  delayMicroseconds(10);
  digitalWrite(trig, LOW);

 int durations = pulseIn(echo, HIGH);
 return durations*0.034 / 2;
}

void loop() {
  // put your main code here, to run repeatedly:
float distance = readDistanceCM();
Serial.print("Jarak Kereta Api: ");
Serial.println(readDistanceCM());

if (distance <= 200){
  myservo.write(90);
  delay(15);
  tone(buzzer, 1000);
  delay(200);
  tone(buzzer, 500);
  delay(200);
}
else {
  myservo.write(0);
  noTone(buzzer);
}
}