I am working with NFC/RFID on Android. I have to read cards with RFID, store the information, and trigger an action when previously stored cards are read again.
It seems uid returned by tag.getId() are randomized every time I tap a card.
What would be the best way to go about identifying NFC connections? Which information is permanent when it comes to NFC? Phones have IMEI that uniquely identifies a device. Do passive RFID cards have anything similar?
Edit (also included in comment): I just downloaded the wakdev NFC Tools app that stdunbar suggested. The app shows that tag type is ISO 14443-3A. Technologies available are NfcA, MifareClassic, and NdefFormattable. Also in the NFC Tools app, my RFID card's serial number does not change every time I tap. I want to access that serial number. The serial number is in the format hh:hh:hh:hh, where each h is a hex digit.