#include <LiquidCrystal.h>
// initialize the library with the numbers of the interface pins
LiquidCrystal lcd(12, 11, 10, 9, 8, 7);
int sensorPin = 0; // pin signal LDR dihubungkan ke Port Analog 0 Arduino
int ledPin = 13; // pin untuk LED
int sensorValue = 0; // variable nilai yg dihasilkan sensor
int buzzerPin = 4;
void setup()
{
  pinMode(ledPin, OUTPUT);
  lcd.begin(16, 2);
  lcd.setCursor(3, 0); // set cursor to column 0, row 0 (the first row)
  lcd.print("WARNING!!!"); // change this text to whatever you like. keep it clean.
  lcd.setCursor(3, 1); // set cursor to column 0, row 0 (the first row)
  lcd.print("WARNING!!!"); // change this text to whatever you like. keep it clean.
  Serial.begin(9600); // untuk membaca data pada serial port di layar monitor
}
void loop()
{
  sensorValue = analogRead(sensorPin); // membaca nilai dari sensor:

  Serial.println(sensorValue); // menulis nilai sensor di layar monitor
  if (sensorValue <= 500 ) // tentukan batas intensitas cahaya 0 - 1024
  {
    lcd.display();
    digitalWrite(ledPin, HIGH); // menyalakan lampu LED (on)
    tone(buzzerPin, 600);
    delay(500);
    tone(buzzerPin, 500);
    delay(500);
  }
  else
  {
    lcd.noDisplay();
    digitalWrite(ledPin, LOW); // mematikan lampu LED (off)
    noTone(buzzerPin);
  }
}