#include <LiquidCrystal_I2C.h>
#include <DHT.h>
#define I2C_ADDR    0x27
#define LCD_COLUMNS 20
#define LCD_LINES   4
#define LED 9
#define rele 4


float temps = 21.0;
float hist = 0.5;


#define DHTPIN 2

DHT dht(DHTPIN, DHT22);

LiquidCrystal_I2C lcd(I2C_ADDR, LCD_COLUMNS, LCD_LINES);

void setup() {

  lcd.init();
  lcd.backlight();
  dht.begin();
  Serial.begin(9600);
  pinMode(LED, OUTPUT);
  pinMode(rele, OUTPUT);

}


void loop() {
  delay(1000);

  float temp = dht.readTemperature();
  float hum = dht.readHumidity();

  
  lcd.setCursor(4, 0);
  lcd.print("Homerseklet:");
  lcd.setCursor(7, 1);
  lcd.print(temp);
  lcd.setCursor(12, 1);
  lcd.print("C");
  lcd.setCursor(4, 2);
  lcd.print("Paratartalom:");
  lcd.setCursor(7, 3);
  lcd.print(hum);
  lcd.setCursor(12, 3);
  lcd.print("%");

 if (temp < temps - hist) {
    digitalWrite(LED, HIGH); 
    digitalWrite(rele, HIGH);
  } 
  else
if(temp > temps + hist){
    digitalWrite(LED, LOW);
    digitalWrite(rele, LOW); 
  }


}