#include <LiquidCrystal_I2C.h>
#define LDR_PIN  2
//LDR Characleristict
const float GAMMA = 0.7;
const float RL10 = 50;
LiquidCrystal_I2C lcd(0x27,16,2);
void setup(){
  pinMode(LDR_PIN, INPUT);
  lcd.init();
  lcd.backlight();
}
void loop(){
  int analogValue = analogRead(A0);
  float voltage = analogValue / 1023. *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);
}