#include <LiquidCrystal.h>
#define LDR_PIN 2

// LDR Characteristics
const float GAMMA = 0.7;
const float RL10 = 50;
const int rs = 12, en = 11, d4 = 5, d5 = 4, d6 = 3, d7 = 2;
LiquidCrystal lcd(rs, en, d4, d5, d6, d7);

void setup() {
  pinMode(LDR_PIN, INPUT);
}

void FotoResistor(){
  lcd.setCursor(0,0);
  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.print("Lux: ");
  lcd.print(lux);
  delay(100);
}

void loop() {
  FotoResistor();
}