i need help my coding for my fyp
Right at the start of your loop you have this (and other similar constructs):
if ( ! mfrc522.PICC_IsNewCardPresent()) {
    return;
}

That means that if no new card is present on reader 1 then the rest of the loop is ignored. Nothing else can happen.
You need to restructure your whole program so that it works in the complete opposite way - instead of saying &quot;If there's no card do nothing&quot; you should say &quot;If there is a card then do something&quot;.