1. Get the RFID Card Code

Using your smartphone (it has to be NFC capable) and the App NFC Tools (wakdev):

The Serial Number is the RFID code. It is also called UID (unique permanent identification) and is burned-in during the manufacturing process. It usually consists of 8 hexadecimal digits. But there are Cards with 14 or 20 digits.

To use this RFID code in Odo, you should remove the colons ":" and use only small letters. Like this:

Example with 8 digits:   67:86:8F:5F -->  67868f5f

Example with 14 digits:   04:5A:51:6A:B0:57:81 -->  045a516ab05781

2. Update the "RFID Card Code" field