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Open-Source, Multitouch Display

Engineers are building inexpensive, tabletop, touch-screen displays and sharing the instructions online.

The iPhone popularized the idea of multitouch displays, and just last month, Microsoft brought the concept to a larger screen by releasing Surface, a multitouch table with a hefty $10,000 price tag. But now engineers at Eyebeam, an art and technology center based in New York, have created a scaled-down open-source version of Surface, called Cubit. By sharing the Cubit’s hardware schematics and software source code, the engineers are significantly reducing the cost of owning a multitouch table. But they’re also fostering innovation by giving engineers an open platform on which to develop novel multitouch applications–something that they’ve previously lacked.

Hands-on hardware: Cubit is an open-source, multitouch, tabletop display, similar to Microsoft’s Surface but less expensive and requiring assembly. The top picture shows a user whose fingers are leaving traces on the table’s surface. The bottom picture shows the Cubit unit, fully assembled.

Addie Wagenknecht, a fellow at Eyebeam, designed Cubit in an attempt to “demystify multitouch.” She and her collaborator Stefan Hechenberger “wanted to prove that anyone could build [a multitouch table] if they had a few simple things,” she says. In addition to making Cubit software available online, Wagenknecht is selling various do-it-yourself kits that include parts and instructions, aimed at people with a range of engineering skills. Putting together a personal multitouch table could cost anywhere from $500 to $1,000, depending on the type of hardware used, Wagenknecht says.

Multitouch displays are not new technology; in fact, they’ve been built in research labs for decades. Mitsubishi Electric Research Labs created an iconic multitouch table called DiamondTouch; more recently, Jeff Han, founder of Perceptive Pixel, based in New York, developed wall-sized multitouch screens that he sells to corporations and major government agencies. But because of the falling costs of many touch-screen components, such as infrared light sources and small cameras and projectors, it’s now becoming feasible for people without access to a lab or venture-capital money to make their own multitouch displays.

Microsoft’s Surface has an image projector, infrared-light emitters, and five cameras nestled in its base. According to Kyle Warnick, a Microsoft marketing manager, both the projector and the infrared emitter shine onto the tabletop from underneath. When an object such as a finger or a cell phone is in contact with the surface, it reflects the infrared light in a characteristic way, and the reflection is picked up by the cameras below. Currently, Microsoft has no plans to open the hardware or software of the system to developers.

Wagenknecht says that her system works in a similar way. Cubit is a boxy table with a clear surface. The single camera inside the table can be a simple webcam with an added infrared filter, and a small image projector can be purchased for about $300. Wagenknecht says that a user simply needs to plug the webcam into a computer, install software available on the Cubit project’s site, plug in the projector, and project images onto the screen. In her kit, she includes a tabletop screen that has a coating that makes it easier for the camera to track objects, she says. Also included in the kit are strips of infrared LEDs that shine light onto the back of the screen, much like the infrared light sources that Microsoft uses.

Do it yourself: Researchers at Eyebeam, an engineering and design firm, sell kits that let people build their own multitouch tables. In this picture, the Cubit frame is completely disassembled. To make the display functional, users must add an inexpensive video camera and a projector, among other pieces of hardware.

Cubit will be on display in San Mateo, CA, this weekend at the Maker Faire, a showcase for do-it-yourself technology, arts, and crafts. Other open-source multitouch projects will also be represented. A team of independent engineers will demonstrate a multitouch table whose design is similar to that of Jeff Han’s displays. In this system, the infrared light that’s detected by the cameras is injected into the screen from the edges, bouncing inside the screen, trapped until an object touches the screen to scatter it. In addition, Johnny Lee, a graduate student from Carnegie Mellon University, in Pittsburgh, is presenting another multitouch project in which he uses the infrared camera of a Wii controller to make an interactive whiteboard for less than $50.

Projects like these illustrate two important trends in technology, says Tim O’Reilly, founder of O’Reilly Media, the publishing company whose Make and Craft magazines put on the Maker Faire. First, the falling cost of hardware enables people to play with high technology without taking a large financial risk. Second, people are forming online communities, such as Instructables.com and wikiHow.com, to share their ideas, solve problems, and start collaborative projects.

Traditionally, O’Reilly says, the open-source community has focused on software, but in recent years, there’s been a push to share more information about hardware. “What we’re seeing is, hackers are engaging in the world of things in the way that they used to in the world of software,” he says. And the more people are able to contribute to building and improving technology, the more chance there is for innovation.

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