I have reviewed rfidmifare.doc.
I want to keep an led on as long as any RFID card with a readable uid is present.
All the examples use mfrc522.isNewCardPresent() which won't work for my needs.
I need to keep reading to see if any card is still there and keep an LED light. If a card is not there (no uid), then turn the led off.
Documentation states to do a .PICC_IsNewCardPresent() .PICC_RequestA() .PICC_WakeupA()
before .PICC_ReadCardSerial
.IsNewCardPresent compiles, but the other 2 don't.
I tried
if (mfrc522.PICC_RequestA() && mfrc522.PICC_ReadCardSerial()) { . . . .
and
if (mfrc522.PICC_WakeUp() && mfrc522.PICC_ReadCardSerial()) { . . . .
but got
"no matching function for call to 'MFRC522::PICC_RequestA()'"
So how would I do a mfrc.isCardPresent()? or simply put get a valid uid without doing a .IsNewCardPresent?