#include <LiquidCrystal_I2C.h>
#include "DHT.h"

#define DHTPIN 2     
#define DHTTYPE DHT22   // DHT 22  (AM2302), AM2321

DHT dht(DHTPIN, DHTTYPE);

LiquidCrystal_I2C lcd(0x27, 20, 4);  
float temperature;
float humidity;
int Sensor_ldr;
int ldr = A0;

int buttonpin = 3;
int buttonState = 0; 

boolean chk_btn = true ;

int Relay1 = 4;
int Relay2 = 5;

int led = 7;

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

float voltage ;
float resistance;
int lux ;


void setup() {
   Serial.begin(115200);
   lcd.init();
   lcd.backlight();
     dht.begin();
     lcd.setCursor(1, 0);
     lcd.print("Hello, BKK!");
     delay(1000);
  pinMode(Relay1, OUTPUT);
  pinMode(Relay2, OUTPUT);
  pinMode(buttonpin, INPUT);
  pinMode(led, OUTPUT);
  lcd.clear();

}
void loop() { 
  button_press();
  Read_temp();
  Read_ldr();
  Monitor_lcd();
}

void button_press(){
  buttonState = digitalRead( buttonpin); 
    if (buttonState == 0 && chk_btn ) {
       chk_btn = false ;
    }
    else if (buttonState == 0 && chk_btn == false) {
       chk_btn = true ;
    }
    
    else if (buttonState == 1 && chk_btn == false) {
      
      Serial.println("on");
      digitalWrite(led, HIGH);
    } 
    else if (buttonState == 1 && chk_btn ) {
     
      Serial.println("off");
      digitalWrite(led, LOW);
    }
  
    // Delay a little bit to avoid bouncing
    delay(100);
}

void Read_ldr(){
   Sensor_ldr = analogRead(ldr);
   voltage = Sensor_ldr / 1024. * 5;
   resistance = 2000 * voltage / (1 - voltage / 5);
   lux = pow(RL10 * 1e3 * pow(10, GAMMA) / resistance, (1 / GAMMA));
     if (lux >= 600){
           digitalWrite(Relay2, HIGH);
      }
      else {
            digitalWrite(Relay2, LOW);
      }
}

void Read_temp(){
  temperature = dht.readTemperature();
  humidity = dht.readHumidity();

  if (isnan(temperature) || isnan(humidity)) {
    Serial.println(F("Failed to read from DHT sensor!"));
    return;
  }
   delay(500);
      if (temperature >= 40){
           digitalWrite(Relay1, HIGH);
      }
      else {
            digitalWrite(Relay1, LOW);
      }
}

void Monitor_lcd(){
  lcd.setCursor(1, 0);  lcd.print("Temp : ");
  lcd.setCursor(8, 0);  lcd.print(temperature);
  lcd.setCursor(14, 0);  lcd.print("*C");

  lcd.setCursor(1, 1);  lcd.print("Ldr : ");
  lcd.setCursor(7, 1);  lcd.print( "    ");
  lcd.setCursor(7, 1);  lcd.print( lux);
  lcd.setCursor(13, 1);  lcd.print("lux");
}