DEF CON is a completely different environment compared the Black Hat. DEF CON is mainly geared to the personal hacker. While Black Hat is meant for security professionals in large companies looking for better ways to protect their company. I was only able to attend one of the talks on the first day because it was sharing the last day of Black Hat and there's a bunch going on.
Major Malfunction and Zac Franken
This session was about a inexpensive alternative to the ProxMark3. The RFIDler was a kickstarter campaign that allowed for reading, writing, and emulating of 125Mhz RFID cards. In the name of the device-they use SDR for Software Define Radio because they are doing the modulation in software. This allows for you to easy switch between different RFID cards. By inexpensive-I mean the device cost $100 at the con. They also made the device so it would be multi platform for easy use between different systems. They did this by managing the the whole system from a chip on the board. You then just use the usb<->serial interface to talk to the firmware on the chip. Just sending commands over this serial interface allows you to read, write, and emulate RFID cards.
I myself bought a RFIDler at DEFCON and will be playing around with it in my free time.