Disappearing Mobile Devices

In this paper, Ni and Baudisch look ahead to the future of mobile devices. As they point out, the primary limiting factor to the miniaturization of mobile devices is the need for user interaction. They try to extrapolate ways of interacting with a device that is essentially of size zero. At this miniscule size, they are left with three variations of touch:

• Touch
• Pressure
• Motion

Of these, they eliminate pressure, since it is limited by where the device is located and how many different inputs can be consistently entered. They conclude the paper with two user studies, one on marking eight directions, and the other on entering letters of the alphabet. The first test had participants using an optical mouse held in one hand, while entering directions with the other hand. Results of this study showed that users entered the wrong direction anywhere from 2.5% to 6.7% of the time, making error rate mostly independent of direction (by one-way repeated-measures ANOVA).

In the second test, users were asked to enter letters in the form of a unistroke alphabet. In this case, a modified version of Palm's Graffiti and another alphabet known as EdgeWrite were used. Interestingly enough, Graffiti system resulted in many more errors, while the EdgeWrite system performed at a level comparative to current device applications.

I liked how this paper looked ahead to a problem that will be faced in the future, and was able to formulate a user-study that allowed the researchers to generate useful results. Future "disappearing device" designers will be able to use this paper to develop a user interface that is much more usable. I couldn't see any flaws in the paper, unless of course these devices never are created. Even still, the paper is an interesting look at the possibility of such devices. Future work would probably be to develop a system of providing output to the user as well as accepting input. I would look at colored LEDs and/or tactile feedback as starting points.