#include <dht.h> // library for DHT22 sensor
#include <LiquidCrystal_I2C.h> // library for I2C LCD
#include <Wire.h> // library for I2C communication

#define DHT22_PIN 2 // pin for DHT22 sensor
#define RELAY_PIN 8 // pin for relay module

dht DHT; // create instance of DHT22 sensor
LiquidCrystal_I2C lcd(0x27, 16, 2); // create instance of I2C LCD

float hum; // variable to store humidity value
float temp; // variable to store temperature value

void setup() {
  Serial.begin(9600);
  lcd.init(); // initialize LCD
  lcd.backlight(); // turn on LCD backlight
  lcd.setBacklight(HIGH);
  pinMode(RELAY_PIN, OUTPUT); // set relay pin as output
}

void loop() {
  int chk = DHT.read22(DHT22_PIN);
  hum = DHT.humidity;
  temp = DHT.temperature;

  lcd.setCursor(0, 0);
  lcd.print("Humidity: ");
  lcd.print(hum);
  lcd.print("%");
  lcd.setCursor(0, 1);
  lcd.print("Temp: ");
  lcd.print(temp);
  lcd.println(" Celcius");

  if (temp > 25) { // if temperature is above 25°C, turn on the fan
    digitalWrite(RELAY_PIN, HIGH);
  } else {
    digitalWrite(RELAY_PIN, LOW); // otherwise, turn off the fan
  }

  delay(2000); // wait for 2 seconds before taking the next reading
}