#include <LiquidCrystal_I2C.h>

#define LDR_PIN 4

LiquidCrystal_I2C l(0x27, 20, 4);

void setup() {
  pinMode(LDR_PIN, INPUT);
  l.init();
  l.backlight();
}

void loop() {
  l.setCursor(2, 0);
  l.print("Room: ");
  if (digitalRead(LDR_PIN) == LOW) {
    l.print("Light!");
  } else {
    l.print("Dark !!! ");
  }
  delay(100);
}