#include <LiquidCrystal_I2C.h>

#define LED_PIN 2
int inputPin = 3;               
int pirState = LOW;             
int val = 0;  

const float GAMMA = 0.7;
const float RL10 = 50;

LiquidCrystal_I2C lcd(0x27, 16, 2);

void setup() 
{
  pinMode(LED_PIN, OUTPUT);
  pinMode(inputPin, INPUT);     
  Serial.begin(9600);

  lcd.init();
  lcd.backlight();
  lcd.clear();
}

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(0, 0);
  lcd.print("Cahaya: ");
  if (lux > 100) 
  {
    lcd.print("Terang");
    digitalWrite(LED_PIN, LOW);
    
  } 
  else 
  {
    lcd.print("Gelap  ");
    val = digitalRead(inputPin);
  
  if (val == HIGH) 
    {            
    digitalWrite(LED_PIN, HIGH);  
    if (pirState == LOW) 
      Serial.println("Gerakan Terdeteksi!");
      lcd.setCursor(0, 1);
      lcd.print("Ada Obyek  ");
      delay(8000);
      pirState = HIGH;
    } 
     else 
    {
    digitalWrite(LED_PIN, LOW); 
    if (pirState == HIGH) 
      Serial.println("Tidak Ada Gerakan!");
      pirState = LOW;
    }
  }

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