#include <LiquidCrystal_I2C.h>

#define LDR_PIN 2

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

LiquidCrystal_I2C lcd(0x27, 20, 4);
 int openButton = 13; //ปุ่มเปิด
 int closeButton = 12; //ปุ่มปิด
 int buttonStatus = 0;
 int Relay = 6;
 
void setup() {
  Serial.begin(9600);
  pinMode(LDR_PIN, INPUT);
  pinMode(openButton, INPUT);
  pinMode(closeButton, INPUT);
  pinMode(Relay, OUTPUT);
 
  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));

  if (digitalRead(openButton) == 1)
  {
    buttonStatus = 2; 
    delay(100);
    Serial.println("START"); 
    
  }
  
  else if (digitalRead(closeButton) == 1)
  {

    buttonStatus = 1; 
    delay(100);
    Serial.println("STOP");
    
  }

 if(buttonStatus == 2){
   
lcd.setCursor(0, 1);
  lcd.print("Lux: ");
  lcd.print(lux);
  lcd.print("          ");
  lcd.setCursor(2, 0);
  lcd.print("Room: ");
  if (lux > 300) {
    lcd.print("Light");
    digitalWrite(Relay, HIGH); // ส่งให้ไฟติด
  delay(500);
  } else {
    lcd.print("Dark  ");
  digitalWrite(Relay, LOW); // ส่งให้ไฟดับ

  delay(100);
}

 }
else if (buttonStatus == 1)
{
lcd.clear();
digitalWrite(Relay, LOW); // ส่งให้ไฟดับ
    delay(500);
}
}