#include <Wire.h> 
#include <LiquidCrystal_I2C.h>
LiquidCrystal_I2C lcd(0x27, 16, 2);
const int trigPin = 12;
const int echoPin = 11;
int cahaya = A2;
int ldr;
long duration;
int distance;
int buzzer = 4;
int led = 3;

void setup() 
{
lcd.init();
lcd.backlight();
lcd.setCursor(0,0);
lcd.print("       FIQRI R.S");
lcd.setCursor(0,1);
lcd.print("NIM : D412021062");
delay (3000);

pinMode(trigPin, OUTPUT); // Sets the trigPin as an Output
pinMode(echoPin, INPUT);// Sets the echoPin as an Input
pinMode(cahaya, INPUT);
pinMode(buzzer, OUTPUT);
pinMode(led, OUTPUT);
Serial.begin(9600); // Starts the serial communication
}

void loop() 
{
lcd.clear();
digitalWrite(trigPin, LOW);
delayMicroseconds(2);
ldr = analogRead(cahaya);

// Sets the trigPin on HIGH state for 10 micro seconds
digitalWrite(trigPin, HIGH);
delayMicroseconds(10);
digitalWrite(trigPin, LOW);

// Reads the echoPin, returns the sound wave travel time in microseconds
duration = pulseIn(echoPin, HIGH);

// Calculating the distance
distance= duration*0.034/2;

// Prints the distance on the Serial Monitor
Serial.print("Distance: ");
Serial.println(distance);
Serial.print("Cahaya: ");
Serial.println(ldr);
lcd.backlight();
  lcd.setCursor(0,0);
  lcd.print("Distance: ");
  lcd.print(distance);
  lcd.print(" cm");
  delay (500);

  if (distance <= 15){
    lcd.setCursor(3,1);
    lcd.print("bahaya");
    digitalWrite (buzzer, HIGH);
    delay (1000);
  }
  if (15< distance < 50 ){
    lcd.setCursor(4,1);
    lcd.print("siaga");
    delay (1000);
  }
  else {
    lcd.setCursor(5,1);
    lcd.print("aman");
    digitalWrite (buzzer, LOW);
    delay(1000);
  }

  if (ldr <= 500){
    digitalWrite (led, HIGH);
    delay(1000);
  }
  else {
    digitalWrite (led, LOW);
    delay(1000);
  }
}