#include <LiquidCrystal_I2C.h>
// Adresse des LCD-Displays meistens 0x27 oder 0x3F
LiquidCrystal_I2C lcd(0x27, 16, 2);


const int LED_BLINK_TIME = 500;
const float BETA = 3950;            // Koeffizient des NTCs

int timeLED = 0;
bool statusLED = false;


// ----------------------------------------------------

void setup()
{
  Wire.begin(8);

  timeLED = millis();

  Serial.begin(9600); //Kommunikation starten

  pinMode(8, OUTPUT);
  pinMode(9, OUTPUT);
  pinMode(7, INPUT_PULLUP);

  lcd.init();
  lcd.backlight();

  lcd.setCursor(0, 0); // Spalte 0, Zeile 0
  lcd.print("Temp:");
  lcd.setCursor(12, 0);
}

// ----------------------------------------------------

void loop()
{
  int sensorWert = analogRead(A0);

  // Temperatur < 0°C
  if (sensorWert > 788)
  {
    if (millis() - timeLED > LED_BLINK_TIME)
    {
      statusLED = !statusLED;
      digitalWrite(8, statusLED);

      timeLED = millis();
    }
  }

  // Temperatur >= 0°C
  if ((sensorWert < 788) || (sensorWert == 788))
  {
    digitalWrite(9, HIGH);
  }
  else
  {
    digitalWrite(9, LOW);
  }

  analogRead(A0);
  Serial.println(sensorWert);
  delay(250);

  float Grad = 1 / (log(1 / (1023. / sensorWert - 1)) / BETA + 1.0 / 298.15) - 273.15;

  lcd.setCursor(6, 0);
  lcd.print(Grad, 2);
  lcd.print(char(223));
  lcd.print("C ");
}