by Joe Grand
Every summer, thousands of hackers and computer security enthusiasts descend into Las Vegas for
DEFCON ( www.defcon.org) — the largest and oldest continuously running event of its kind. It's a
mix of good guys, bad guys, government officials, and everyone in between, all focused on having
fun, sharing technical information, seeing old friends, and learning new things. This is the third
year in a row that I've had the honor of designing the conference badge for DEFCON. Unlike other
conferences where boring plastic or metal badges are used, DEFCON has been setting the trend
since 2006 in giving out full-featured, active electronic badges to their attendees and challenging
them to do something unique with their new-found technology.
This article highlights my design process and the problems
that I encountered during the creation of the DEFCON
16 Badge. Hopefully, you'll be able to learn from my mistakes or build on my work to enhance your own endeavors.
A Brief History of the DEFCON Badge
The previous years' electronic badge designs each had
their own set of unique challenges, interesting lessons, and
frustrating problems. The DEFCON 14 badge was a round
PCB with complicated cutouts of graphical elements and
consisted of a six pin Microchip PIC10F202, two jumbo
blue LEDs, and a single CR2032 Lithium coin cell. The
badge had four different LED modes (on, blinking,
alternating, random) and a Microchip ICD2 programming
interface for attendees to load their own customized
firmware onto the badge. We didn't know what to expect
when we started handing them out to conference
attendees, but the response was overwhelming, which led
to a new badge design for the next year.
I upped the ante and the technical complexity of the
DEFCON 15 badge by using a Freescale MC9S08QG8, a
95 LED matrix (five columns by 19 rows) for custom
scrolling text messages, capacitive touch sensors, and
unpopulated areas for accelerometer and 802.15.4 wireless
support. You can read all about the trials and tribulations
of the DEFCON 15 badge in the July 2008 issue of
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March 2009
Nuts & Volts. Even with the success of the badge, I felt that
I had over-engineered it and that it contained too much for
attendees to digest over the weekend. So with DEFCON 16,
we wanted to have an electronic badge that could still be
personalized in some way, but without a lot of "noise" to
detract people from the key features and turn them off
from hacking their badge.
Design Goals
The primary goal of the DEFCON 16 badge was to
incorporate a file transfer feature to allow an attendee to
transfer files to another attendee using his or her badge, not
unlike the "beaming" capability of PDAs and smartphones.
Attendees would load their desired file — be it a business
card, picture, poem, or write-up of their latest discovery or
research — onto a SecureDigital (SD) card, insert it into the
badge, and transfer it to a willing recipient via infrared. Just
like last year's badge in which attendees could display a customized text message onto it, the file transfer functionality
of DEFCON 16 would meet this same "personalization"
goal, allowing attendees to make their badge unique based
on what sort of information they chose to share with others.
With over 8,500 attendees expected at the conference,
I assumed that only a small percentage would actually take
advantage of the file transfer capabilities, even though that
was to be the core functionality of the badge. I wanted the
