#include <LiquidCrystal_I2C.h>

int ldrPin = A0;
int ledPin = 2;
const float GAMMA = 0.7;
const float RL10 = 50;

LiquidCrystal_I2C lcd(0x27,16,2);
void setup() {
pinMode(ledPin, OUTPUT);
lcd.init();
lcd.backlight();
}

void loop() {
  int ldrValue = analogRead(ldrPin);
  float voltase = ldrValue / 1024. * 5;
  float resistansi = 2000 * voltase / (1-voltase / 5);
  float kecerahan = pow(RL10 * 1e3 * pow(10, GAMMA) / resistansi,(1/GAMMA));
  lcd.setCursor(0,0);
  lcd.print("Cahaya: ");
  if(kecerahan > 50){
    lcd.print("Terang");
    digitalWrite(ledPin, LOW);
  }


else{
  lcd.print("Gelap ");
  digitalWrite(ledPin, HIGH); 
  } 
  lcd.setCursor(0, 1);
  lcd.print("Lux: ");
  lcd.print(kecerahan);
  lcd.print("   ");
  delay(100);
}