#define LDR 0                               //LDR pada pin A0
#define LED 2
#include <LiquidCrystal_I2C.h>
const float GAMMA = 0.7;
const float RL10 = 50;
LiquidCrystal_I2C lcd(0x27, 16, 2);
void setup() {
  pinMode(LED, OUTPUT);
  lcd.init();
}

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));

  lcd.setCursor(2,0);
  lcd.print("Cahaya: ");
  if(lux > 50){
    lcd.print("Terang!!");
    digitalWrite(LED, LOW);
  }else{
    lcd.print("Gelap!");
    digitalWrite(LED, HIGH);
  }
  lcd.setCursor(0,1);
  lcd.print("Lux: ");
  lcd.print(lux);
  lcd.print("...........");
  delay(100);
}