#include <LiquidCrystal_I2C.h>

#define I2C_ADDR    0x27
#define LCD_COLUMNS 20
#define LCD_LINES   4

LiquidCrystal_I2C lcd(I2C_ADDR, LCD_COLUMNS, LCD_LINES);

void setup() {

  lcd.begin(16, 2); //Setup LCD Display
  lcd.backlight();

  pinMode(A0, INPUT); //Input Potentiometer

}

void loop() {

  int potValue = analogRead(A0); //Potentiometer auslesen

  float ratio = (float(10000) / float(1023));

  float widerstand = (1023 - potValue) * ratio;

  lcd.clear(); //Display leeren

  lcd.setCursor(5, 1); //Cursor zentrieren
  lcd.print(widerstand); //Widerstand anzeigen
  lcd.print(" \364"); //Ohm-Zeichen

  delay(500);

}