I am using the ID12-LA RFID reader with an Arduino Pro Mini (5V, 16MHz). I am also using the software serial library to read the serial data form the reader.
Initially the serial data is being read properly, however after several reads (i.e. maybe around 10 - 20) the serial seems to malfunction and calling the read() function always returns a 0.
Right now the only way I can fix this is if I reset the Arduino. Also note that when I reset the Arduino the RFID reader is staying powered up (so it's not being reset or anything; this means the issue seems to be from the Arduino).