This year's Defcon badge has a persistent display

It's one of the best things about the Defcon hacking conference, and one of its most closely guarded secrets: the programmable badge that's handed out to show attendees every year.

Designed by legendary hardware hacker Joe Grand, this year's badge will have a programmable persistent display.

Grand doesn't want to give out many details about this year's badge. That would spoil the surprise (and maybe help counterfeiters). But in an interview, he said that this year's badges will contain little 128 by 32 pixel screens built by Ohio's Kent Displays.

"It's just a really really awesome part," he said in an interview Tuesday. "I've wanted to use a display for a while, and the cost is just too high."

Grand worked a 5 x 19 LED marquee into the 2007 badge, but this year's full fledged display takes things to a new level.

Kent has been around since 1995, selling what are known as cholesteric liquid crystal displays. These displays squish liquid crystal molecules between two pieces of glass spaced about five microns apart. The molecules are twisted in such a way that they are either perpendicular to the glass or not.

Parallel molecules show nothing on the Defcon badge's blue-and-white displays; turn them perpendicular, and you get color. By applying an electric charge, the molecules can be moved between these two states, creating an image that lasts, even without power, similar to the e-ink in Amazon's Kindle.

Grand's badges are a highlight of the conference. He invites attendees to join him in a hardware hacking contest run out of a lab that's set up in the rooms above the conference floor. Last year close to 40 attendees took out soldering irons and started attaching components to the badges, turning them into lie detectors, remote control devices and -- last year's winner -- an entire anti-surveillance system.

But, said Grand, "No real conference badges have ever had a display."

A few years ago, a Boston company called Ntag Interactive, came close however. It built an "event data management" system designed around a badge with this type of display that was supposed to add interactive elements -- games and messages, for example -- to event badges. Ntag went bankrupt in early 2009.

Robert McMillan covers computer security and general technology breaking news for The IDG News Service. Follow Robert on Twitter at @bobmcmillan. Robert's e-mail address is robert_mcmillan@idg.com

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