#include <LiquidCrystal_I2C.h>

int led1 = 25;  
int led2 = 2;  
int led3 = 15;  
#define LDR_PIN 12

// LDR Characteristics
const float GAMMA = 0.7;
const float RL10 = 50;

LiquidCrystal_I2C lcd(0x27, 20, 4);

void setup() {
  pinMode(LDR_PIN, INPUT);
  pinMode(led1, OUTPUT);
  pinMode(led2, OUTPUT);  
  pinMode(led3, OUTPUT);    
  lcd.init();
  lcd.backlight();
}

void loop() {
  int analogValue = analogRead(12);
  float voltage = analogValue / 4095. * 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) {
    digitalWrite(led2, LOW);
    digitalWrite(led3, HIGH);
    lcd.print("Light!");
    
  } else {
    digitalWrite(led2, HIGH);
    digitalWrite(led3, LOW);
    lcd.print("Dark  ");
  }
  int lux2 = map(lux,0,100000,0,255);
  analogWrite(led1,lux2);
  lcd.setCursor(0, 1);
  lcd.print("Lux: ");
  lcd.print(lux);
  lcd.print("          ");

  delay(500);
}