#include <LiquidCrystal_I2C.h>

LiquidCrystal_I2C lcd(0x27, 16, 2);

byte customChar[8] = {
	0b10101,
	0b01010,
	0b11111,
	0b11011,
	0b01110,
	0b10101,
	0b00100,
	0b10101
};

uint8_t n = 0;
uint8_t k = 1;
float i=0;
unsigned long previousMillis;

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

  lcd.createChar(0, customChar);
  
  zobraz();
  previousMillis=millis();
}

void loop() {
  unsigned long currentMillis=millis();
  if(currentMillis-previousMillis>=250){
    previousMillis=currentMillis;
    zobraz();
  }
}

void zobraz(){
  lcd.clear();
  lcd.setCursor(n,0);
  n=n+k;
  k=n==0||n==15?-k:k;
  lcd.write((byte)0);
}