//MUHAMMAD SYIHABUDIN RIYADI
//21060027
//REG SORE
#include <LiquidCrystal_I2C.h>
#define LDR_PIN 2

const float GAMMA = 0.7;
const float RL10 = 50;
LiquidCrystal_I2C lcd(0x27, 20, 4);
void setup() {
  // put your setup code here, to run once:
  pinMode(LDR_PIN, INPUT);
  lcd.init();
  lcd.backlight();
}

void loop() {
  // put your main code here, to run repeatedly:
  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.setCursor(2,0);
  lcd.print("room : ");
  if (lux >= 100) {
    lcd.print("Terang");
  }else if (lux >= 50) {
    lcd.print("Redup  ");
  }else if (lux >= 0) {
    lcd.print("Gelap  ");
  }  
  lcd.setCursor(2, 1);
  lcd.print("Lux  : ");
  lcd.print(lux);
  lcd.print("    ");
  delay(100);
}