Basic code to read IDs from RFID tags using an SL030 reader on a Raspberry Pi

Tries for a few seconds to read a tag on the reader. If a tag is found, its ID is printed to stdout in hex.

1. Install Mike McCauley's C library for Broadcom BCM 2835 (used to access the I2C bus on the Raspberry Pi)
2. Compile the code:

    gcc -static rfid_sl030.c -lbcm2835 -o rfid_sl030

1. Run the code, as root

    sudo ./rfid_sl030

You might need to set the baudrate for the I2C bus to get it to work reliably:

    sudo modprobe -r i2c_bcm2708
    sudo modprobe i2c_bcm2708 baudrate=200000

• rfid_sl030.c - Check for an RFID card on the reader, and if one is present output its ID number to stdout, in hex.
• rfid_read_ultralight.c - Read the contents of a Mifare Ultralight (or NTAG2xx card) and output it to stdout. Assumes there is already a tag present, and that it's an Ultralight (or compatible) type.
• get_first_ndef_text_record.c - Read the contents of a Mifare Ultralight/NTAG2xx tag, parse any contained NDEF records and output the first text record to stdout.