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Thursday, May 01, 2008 Open-Source, Multitouch DisplayEngineers are building inexpensive, tabletop, touch-screen displays and sharing the instructions online. By Kate Greene
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. 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. |
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The Next Generation of iPhone Hacks
02/12/2008
Comments
fennecfanatic on 05/03/2008 at 5:30 AM
2
Actually, the necessary modification to the webcam is to remove its infrared filter and add a visible light filter.
Almost all webcams come with an infrared light filter, which would prevent the infrared interface light from reaching the lens of the camera.
Swapping the filter causes the camera to see only the infrared light reflected by objects on the touch surface, blocking out interference from projector reflection.
Such visible light filters are typically made in the do-it-yourself community by cutting a square from an exposed area on a film negative.
feign on 05/05/2008 at 2:14 PM
1
dandb on 05/03/2008 at 8:54 PM
1
I got to talk to Bob Boie for a while. The guy was amazing. He seemed to turn out incredible inventions at a pretty regular pace.
No one at Bell Labs that I talked to seemed to know what to do with the multitouch pad. I recall they had two ideas: (1) Shift Keys(!), and (2) step on the pad in a shoe store and get a detailed pressure map for your foot, so the salesman can sell you the expensive shoes.
For the multitouch part of my thesis, I used the Sensor Frame, invented by Paul McAvinney, then of Carnegie Mellon, later of Sensor Frame Corp. It could detect up to three fingers in the plane about a quarter inch above the screen. It used optical sensors in the corners of the frame, so it had trouble disambiguating certain finger configurations. Anyway, I saw in a prototype hardware around 1985, I used the technology (just a single sensor)in the VideoHarp around 1986/87, and I used a working Sensor Frame in 1990/1991.
I ended up using the Sensor Frame to make a multifinger drawing program, which was first mentioned in SIGGRAPH 1991, with lots more details in my thesis, and a video in the CHI '92 video proceedings. The program had a two finger gesture similar to the iPhone: pinch to shrink, separate to enlarge, rotate to rotate.
The author Ms. Greene is right when she says the multitouch technology has been around in labs for decades, though the NEC example she cites seems to have first been published in 2000 or so. I hope the two examples from the 1980s I mention are of interest.
Dean Rubine
abb8404 on 05/05/2008 at 11:49 AM
1
Hello
My name is Alejandro Bonilla
I write from Cali - Colombia
I am interested in the cube
that is what it takes to build
I would like to build one for my home;
about this issue please could provide information?
thank you very much
christinadxb on 05/20/2008 at 9:29 AM
10