//RIZKI ADRIAN
//LDR Sensor
#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() {
  pinMode(LDR_PIN, INPUT);
  lcd.init();
  lcd.backlight();
  
}

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("Room: ");
if (lux > 100)  {
  lcd.println("TERANG");
}

if (lux > 50){
  lcd.print("REDUP");
}
if (lux < 50){
  lcd.print("GELAP");
 
}

lcd.setCursor(2, 1);
lcd.print("lux : ");
lcd.print(lux);
lcd.print("     ");
delay(1000);
lcd.clear();
}