Returns either a string containing the id number of the last RFID badge / keytag that was scanned or None if no badges or keytags have been scanned since the last calld to this function.
Resets the RFID reader
Note! Some RFID readers have anti-duplicate scanning functionality built in. Once an rfid badge or keytag is scanned, it will not scan again until a different badge or keytag has been scanned.