RFID- How to detect when a card is removed from the reader

Projects Programming
1

Hey Guys,
I am wroking with rfid mfrc522 readers. I am using 4 readers for my project and they all read data as they should when I scan the tags.
I use this to detect when the reader has started reading:

if (rfidReader0.PICC_IsNewCardPresent() && rfidReader0.PICC_ReadCardSerial()) {
    Serial.println("new card detected");
    isreading0 = true;
    readOnReader0(); 
  }

But how can I check if the reader is still reading that card or has stopped?

Thanks!

3

test that the card is present, readed and has the same serial as previous read

4

@b707 Can you please explain a little bit more, how I can check if it has the same serial?
Thanks!

5

When you call PICC_ReadCard_Serial() it returns true if a card is present and false if is not. You can spot when a card is removed if between one call and the next the return value changes from true to false

6

Read the card serial (see the ReadNUID.ino example from the library) and save it in variable. At next reading do the same and compare actual and saved ID

7

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