#include <LiquidCrystal.h>
int value= 0;
const float gamma = 0.7;
const float rl10 = 50;

LiquidCrystal lcd(12, 11, 10, 9, 8, 7);

void setup() 
{
  pinMode(3, OUTPUT);
  lcd.begin(26,2);
}

void loop() 
{
  value= analogRead(A0);
  float voltage = value / 1024. * 5;
  float resistance = 2000 * voltage / (1 - voltage / 5);
  float lux = pow(rl10 * 1e3 * pow(10, gamma) / resistance, (1 / gamma));

  if(lux < 200)
  {
    digitalWrite(3, HIGH);
    lcd.setCursor(3,1);
    lcd.println("LED is On");
    delay(200);
  }
  else
  {
    digitalWrite(3, LOW);
    lcd.setCursor(3,1);
    lcd.println("LED is Off");
    delay(200);
  }

  lcd.clear();
  lcd.setCursor(0,0);
  lcd.print("Lumen: ");
  lcd.println(lux);
  delay(200);
}