#include <LiquidCrystal_I2C.h>
#define LED_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(LED_PIN, OUTPUT);
  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("Cahaya :");
if(lux>50){
  lcd.print("terang");
  digitalWrite(LED_PIN, LOW);

}else{
  lcd.print("Malam ");
  digitalWrite(LED_PIN, HIGH);
}



  lcd.setCursor(0,1);
  lcd.print("Nilai LUX :");
  lcd.print(lux);
  lcd.print("       ");
  delay(100);
}