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

LiquidCrystal_I2C lcd(0x27,16,2);

//Constants
#define DHTPIN 7
#define DHTTYPE DHT22
DHT dht(DHTPIN, DHTTYPE);

float t = dht.readTemperature();
float h = dht.readHumidity();

void setup()
{
  Serial.begin(9600);
  Serial.println("Temperature and Humidity Sensor Test");
  dht.begin();
  lcd.init();
  lcd.backlight();
}

void loop()
{
  t = dht.readTemperature();
  h = dht.readHumidity();

  Serial.print("Humidity: ");
  Serial.print(h);
  Serial.print(" %, Temp: ");
  Serial.print(t);
  Serial.print(" ° Celcius");

  lcd.setCursor(0, 0);
  lcd.println(" Now Temperature ");

  lcd.setCursor(0,1);
  lcd.print("T:");
  lcd.print(t);
  lcd.print("C");

  lcd.setCursor(9,1);
  lcd.print("H:");
  lcd.print(h);
  lcd.print("%");

  delay(1000);

  static float oldT = t;
  static float oldH = h;
  float newT = t;
  float newH = h;

  if(newT < oldT)
  {
    digitalWrite(3, HIGH);
    tone(12,500);
    digitalWrite(2, LOW);
  }
  else if(newT > oldT)
  {
    digitalWrite(2, HIGH);
    tone(12,600);
    digitalWrite(3, LOW);
  }
  else
  {
    digitalWrite(2, LOW);
    digitalWrite(3, LOW);
    noTone(12);
  }

  oldT = newT;
}