#include <LiquidCrystal_I2C.h>
#define LDR_PIN 2


const float GAMMA=0.7;
const float RL10=50;
LiquidCrystal_I2C lcd(0X27,20,4);
void setup()
{
  pinMode(LDR_PIN,INPUT);

  lcd.init();
  lcd.backlight();
}
void loop()
{
  int analogValue=analogRead(A0);
  float voltage=analogValue/1024.*5;
  float resistance=2000*voltage/(1-voltage/5);
  float lux=pow(RL10*1e3*pow(10,GAMMA)/resistance,(1/GAMMA));

  lcd.setCursor(2,0);
  lcd.print("Room:");
  if(lux>50)
  {
    lcd.print("Light!");

  }
    else
    {
    lcd.print("Dark");
    }
  lcd.setCursor(0,1);
  lcd.print("Lux:");
  lcd.print(lux);
  lcd.print("     ");
  delay(100);
}