#include <LiquidCrystal_I2C.h>

#define LDR_PIN 2

// LDR Characteristics
const float GAMMA = 0.7;
const float RL10 = 50;

int ledPin = 2;
int inputPin = 3;               // choose the input pin (for PIR sensor)
int pirState = LOW;             // we start, assuming no motion detected
int val = 0;

LiquidCrystal_I2C lcd(0x27, 20, 4);

void setup() {
  Serial.begin(115200);
  pinMode(LDR_PIN, INPUT);
  pinMode(ledPin, OUTPUT); 

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

void loop() {
  int analogValue = analogRead(A0);
  val = digitalRead(inputPin);
  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(1, 0);
  lcd.print("Keadaan: ");

  if (lux < 50) {
    if (val == HIGH){
      lcd.print("Malam");
      digitalWrite(ledPin, HIGH);  // turn LED ON
      if (pirState == LOW) {
        lcd.setCursor(0, 1);
        lcd.print("Motion detected!");
        pirState = HIGH;
      }
    }else {
      lcd.print("Malam");
      digitalWrite(ledPin, LOW);
      lcd.setCursor(0, 1);
      lcd.print("No motion !     ");
      pirState = LOW;
    }            // check if the input is HIGH
    
  } else {
    if (val == HIGH){
      lcd.print("Siang");
      digitalWrite(ledPin, LOW);  // turn LED ON
      if (pirState == LOW) {
        lcd.setCursor(0, 1);
        lcd.print("Motion detected!");
        pirState = HIGH;
      }
    }else {
      lcd.print("Siang");
      digitalWrite(ledPin, LOW);
      lcd.setCursor(0, 1);
      lcd.print("No motion !     ");
      pirState = LOW;
    }
  }
  delay(1000);
}