/* 
Project : Arduino Uno is connected with Temperatur sensor (DHT22),
          LCD I2C 2004 and LED.
        
*/
//call library LCD
#include <LiquidCrystal_I2C.h>
// call library DHT sensor
#include <DHT.h>
// definition DHT 22 sensor 
#define DHTTYPE DHT22

// LCD address to 0x27 for a 20 chars and 4 line display
LiquidCrystal_I2C lcd(0x27,20,4);

// Pin for DHT22 and LED
const int dht_pin = 11;
const int led_pin = 9;

//initialize the DHT
DHT dht(dht_pin, DHTTYPE);

void setup() {
  Serial.begin(9600);

// initialize the LCD
  lcd.init();
  lcd.backlight();

  //print a massage to the LCD
  lcd.setCursor(3,0);
  lcd.print("Hello, World!");
  lcd.setCursor(3,1);
  lcd.print("Tell me");
  lcd.setCursor(3,2);
  lcd.print("The temperatur");
  lcd.setCursor(3,3);
  lcd.print("Right now");

  dht.begin();                 //initialize the DHT22
  pinMode(led_pin, OUTPUT);   //LED as output
  delay(5000);                // wait for 5s
  lcd.clear();                //LCD will clear after 5s

}

void loop() {

  // show the temperatur
  lcd.setCursor(3,0);
  lcd.print("Temperatur :");
  lcd.setCursor(13,1);
  lcd.print(String(dht.readTemperature()) + "C");

  // show the humidity
  lcd.setCursor(3,2);
  lcd.print("Humidity :");
  lcd.setCursor(13,3);
  lcd.print(String(dht.readHumidity()) + "%");

  //LED will light up after the temperatur and humidity is displayed
  digitalWrite(led_pin, HIGH);    
  delay(1000);
  digitalWrite(led_pin, LOW);
  delay(5000);  // wait for 5s off than the display will show again the temperatur
 
}