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

LiquidCrystal_I2C lcd(0x27, 16, 2);

// dodaj praznine na početku i kraju da tekst "pliva"
String topText    = "                GEOTECH FORUMS                ";
String bottomText = "                CARL MORELAND WORKS FOR ML                ";

int topIndex = 0;
int bottomIndex = 0;

void setup() {
  lcd.init();
  lcd.backlight();
  lcd.clear();
}

void loop() {
  // gornji red (levo -> desno)
  lcd.setCursor(0, 0);
  lcd.print(topText.substring(topIndex, topIndex + 16));

  // donji red (desno -> levo)
  int revIndex = bottomText.length() - 16 - bottomIndex;
  lcd.setCursor(0, 1);
  lcd.print(bottomText.substring(revIndex, revIndex + 16));

  // pomeraj indekse
  topIndex++;
  if (topIndex > topText.length() - 16) topIndex = 0;

  bottomIndex++;
  if (bottomIndex > bottomText.length() - 16) bottomIndex = 0;

  delay(80); // manja vrednost = brži i glađi "plivajući" efekat
}