#include <LiquidCrystal_I2C.h>
#define LAMPU 8

const float GAMMA = 0.7;
const float RL10 = 50;

LiquidCrystal_I2C lcd(0x27, 16, 2);

void setup() {
  Serial.begin(9600);

  lcd.init();
  lcd.backlight();
  pinMode(LAMPU,OUTPUT);
}

void loop() {
  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));

  Serial.println("analogValue : " + String(analogValue));
  Serial.println("voltage : " + String(voltage));
  Serial.println("resistance : " + String(resistance));
  Serial.println("lux : " + String(lux));  
  Serial.println("----------------------");

  lcd.setCursor(0, 0);
  lcd.print("Ruangan: ");
  if (lux > 50) {
    lcd.print("Terang");
    digitalWrite(LAMPU,LOW); // LAMPU MATI
  } else {
    lcd.print("Gelap ");
    digitalWrite(LAMPU,HIGH); // LAMPU MENYALA
  }

  lcd.setCursor(0, 1);
  lcd.print("Lux: ");
  lcd.print(lux);
  lcd.print("          ");

  delay(1000);
}