13.56 MHz ISO15693 RFID tags
13.56 MHz RFID tags are a great choice for small RC vehicles as they are extremely light weight and do not require a power source. They draw their power from the RF field generated by a 13.56MHz reader such as the TI S6350 reader.
The following tag can be used with the TI S6350 module:
TI HF large rectangle transponder
It can be purchased from Mouser here:
Other standard tags should work. When using smaller tags you may need to mount them on the bottom.
Kyosho RFID Tags
Kyosho RFID tags are ISO15693 tags made by Phillips/NXP. The tags are small and must be mounted on the bottom of the cars for them to be detected. The Kyosho tags come preformatted with data.
UID
Each RFID tag has a unique Unique IDentifier (UID). The UID is 64 bits long. An example of a UID is the following hex:
E007000012C080
This UID is used by the software to track laps for that particular car.