Support library, rfid12, for readers build around the ID Innovations ID-12.
The basic principles of RFID are very simple. A small glass tag encapsulating a unique identification code is affixed to the underside of the model and a trackside/roadside reader charges it up as the model passes by to enable it to transmit its code to the reader. Standard serial data is then available to be passed to a computer.
[STX] [D1] [D2] [D3] [D4] [D5] [D6] [D7] [D8] [D9] [D10] [CS1] [CS2] [CR] [LF] [ETX]
D1-D10 is the actual data, 10 ASCII characters. CS1 and CS2 are 2 ASCII characters that are the (XOR) checksum for the data.
The characters must be converted to hex numbers before calculating the checksum.
D1-D10 = "2 4 0 0 C C 5 7 8 3" becomes 0x24 0x00 0xCC 0x57 0x83
When using a concentrator, for 1 to 8 readers, the STX character is replaced with the reader ID: 'A' … 'H'.
The setup is simple because the line settings are fixed.
Only the device must be specified: com* or /dev/tty*, depending of the used OS.
The RFID serial connection need to bes set to 9600 8N1 (CTS hardware handshake).
After 500ms the read RFID will be automatically reported off. 1)
To buy the MERG kit a membership of MERG is necessary. MERG is a non commercial association ( Verein ) in the UK.
An international, UK based group promoting interest in the application of electronics (including computers) to all aspects of railway modelling.
The annual membership costs 19 GBP a year ( http://www.merg.org.uk/membership.htm ). In case of the RFID kits, the membership fee almost pays back immediately due to the relativ low price of the ID12 readers, MERG offers (compared to other sources like sparcfun ). MERG has also other kits which might be interesting.