This year's Defcon badge has a persistent display

The 128 by 32 pixel display by Kent Displays holds a picture even without a battery

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

Join the Good Gear Guide newsletter!

Error: Please check your email address.

Tags popular scienceDefconsecurityComponentsdisplaysKent Displays

Our Back to Business guide highlights the best products for you to boost your productivity at home, on the road, at the office, or in the classroom.

Keep up with the latest tech news, reviews and previews by subscribing to the Good Gear Guide newsletter.

Robert McMillan

IDG News Service
Show Comments

Cool Tech

ASUS ROG Swift PG279Q – Reign beyond virtual world

Learn more >

D-Link TAIPAN AC3200 Ultra Wi-Fi Modem Router (DSL-4320L)

Learn more >

Crucial® BX200 SATA 2.5” 7mm (with 9.5mm adapter) Internal Solid State Drive

Learn more >

Lexar® Professional 1000x microSDHC™/microSDXC™ UHS-II cards

Learn more >

D-Link PowerLine AV2 2000 Gigabit Network Kit

Learn more >

Gadgets & Things


Learn more >

Lexar Professional 2000x SDHC™/SDXC™ UHS-II cards

Learn more >

Lexar® Professional 1000x microSDHC™/microSDXC™ UHS-II cards

Learn more >

Family Friendly

Lexar® Professional 1000x microSDHC™/microSDXC™ UHS-II cards

Learn more >

Lexar Professional 2000x SDHC™/SDXC™ UHS-II cards

Learn more >

ASUS VivoPC VM62 - Incredibly Powerful, Unbelievably Small

Learn more >

Stocking Stuffer

Lexar Professional 2000x SDHC™/SDXC™ UHS-II cards

Learn more >

Lexar® Professional 1000x microSDHC™/microSDXC™ UHS-II cards

Learn more >

Christmas Gift Guide

Click for more ›

Most Popular Reviews

Best Deals on Good Gear Guide

Latest News Articles


GGG Evaluation Team

Kathy Cassidy


First impression on unpacking the Q702 test unit was the solid feel and clean, minimalist styling.

Anthony Grifoni


For work use, Microsoft Word and Excel programs pre-installed on the device are adequate for preparing short documents.

Steph Mundell


The Fujitsu LifeBook UH574 allowed for great mobility without being obnoxiously heavy or clunky. Its twelve hours of battery life did not disappoint.

Andrew Mitsi


The screen was particularly good. It is bright and visible from most angles, however heat is an issue, particularly around the Windows button on the front, and on the back where the battery housing is located.

Simon Harriott


My first impression after unboxing the Q702 is that it is a nice looking unit. Styling is somewhat minimalist but very effective. The tablet part, once detached, has a nice weight, and no buttons or switches are located in awkward or intrusive positions.


Latest Jobs

Don’t have an account? Sign up here

Don't have an account? Sign up now

Forgot password?