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

#define TASTER 9
#define LED_Bl 8
#define DHTPIN 2
#define DHTTYPE DHT22

LiquidCrystal_I2C lcd(0x27, 16, 2);
DHT dht(DHTPIN, DHTTYPE);

int Interval = 1000;
unsigned long altezeit = millis();



void setup() {
  Serial.begin(9600);
  pinMode(8, OUTPUT);
  pinMode(9, INPUT_PULLUP);
  dht.begin();
  lcd.begin(16, 2);
}

void loop() {
  float sensortemp = 0.0;

  digitalWrite(LED_Bl, schalter());

  if(digitalRead(LED_Bl) == HIGH) {
    if(millis() - altezeit >= Interval){
      sensortemp = dht.readTemperature();
      altezeit = millis();
      lcd.backlight();
      lcd.setCursor(0,0);
      lcd.print("Temperatur: ");
      lcd.setCursor(0,5);
      lcd.print(sensortemp);
    }
  }
  else{
    lcd.noBacklight();
    lcd.clear();
  }
}

bool schalter(){
  bool static status = LOW;
  bool static Flankenmerker = LOW;

  if(digitalRead(TASTER) == LOW && Flankenmerker == LOW){
    Flankenmerker = HIGH;
    status = !status;
    Serial.print("Status: ");
    if( status == HIGH) Serial.println("An");
    else Serial.println("Aus");
    delay(20);
  }

  if(digitalRead(TASTER) == HIGH ){
    Flankenmerker = LOW;
    delay(20);
  }
  return status;
}