#include <LiquidCrystal_I2C.h>
#define ldrPin 2

const float gama = 0.7;
const float rl10 = 50;

LiquidCrystal_I2C lcd(0x27, 20, 4);

void setup() {
  // put your setup code here, to run once:
  Serial.begin(115200);
  Serial.println("Hello, ESP32!");

  lcd.init();
  lcd.backlight();
}

void loop() {
  // put your main code here, to run repeatedly:
  delay(10); // this speeds up the simulation
  int iLDR = analogRead(ldrPin);
  iLDR = map(iLDR, 4095, 0, 1024, 0); 
  float voltage = iLDR / 1024.*5;
  float resistanse = 2000 * voltage / (1-voltage/5);
  float lux = pow(rl10*1e3*pow(10,gama)/resistanse,(1/gama));
  Serial.print("lux = ");
  Serial.println(lux);
  lcd.setCursor(0, 0);
  lcd.print("Room: ");
  if (lux > 500) {
    lcd.print("Light!");
  } else {
    lcd.print("Dark  ");
  }

  lcd.setCursor(0, 2);
  lcd.print("Lux: ");
  lcd.print(lux);
  lcd.print("          ");

  delay(100);
}