Technology has reached the point where full-functioned personal digital assistants (PDAs) and mobile phones are the size of a wristwatch. In the foreseeable future, wireless wrist devices will emerge to handle all of a user's personal information and communication needs, including text messaging and information retrieval. But with these small devices come small screens, which are not conducive to current ways of entering or displaying information. Mobile users also need easily accessible interaction methods that work well under heavy cognitive loads, with multiple and varied tasks, and in environments that can change rapidly. New interaction techniques are required to address the limitations of small devices and how they are used in a wide variety of contexts.

    This presentation will introduce three areas of current research involving the design of interaction techniques suitable for wearable and very small (ultra-mobile) devices. The first area is text entry using keypad, stylus, and thumbwheel techniques. This includes the design of linguistic-based single key press text entry methods (using keypads of varying sizes) that keep letters in alphabetical order while minimizing the number of ambiguous words that a user encounters. The second area is the design and use of pixel-based displays, which convey information using one or more individual lights (i.e., LEDs). Unlike text or icons, information sent to pixel-based displays can be personalized such that only the user knows its meaning, even if it is publicly displayed. Pixels can also be used in conjunction with other forms of output (e.g., text or graphics) in order to maintain desired levels of privacy in otherwise non-private displays. The third area involves the problem of split attention, where we are seeking to understand the human and machine complexities in designing mobile device interfaces for environments where multiple tasks must be attended to.