User Interfaces for Applications on a Wrist Watch M. T. Raghunath and Chandra Narayanaswami Wearable Computing Platforms, IBM TJ Watson Research Center, Yorktown Heights, NY, USA Abstract: Advances in technology have made it possible to package a reasonably powerful processor and memory subsystem coupled with an ultra high-resolution display and wireless communication into a wrist watch. This introduces a set of challenges in the nature of input devices, navigation, applications, and other areas. This paper describes a wearable computing platform in a wrist watch form-factor we have developed. We built two versions: one with a low resolution liquid crystal display; and another with a ultra high resolution organic light emitting diode display. In this paper we discuss the selection of the input devices and the design of applications and user interfaces for these two prototypes, and the compare the two versions. Keywords: Applications; Linux; User Interfaces; Wearable computing; Wrist watch 1. Introduction A wrist watch is an attractive form factor for a wearable computer. It has the advantage of always being with you; and it can be instantly viewed with the flick of the wrist. By compar- ison, devices such as pagers, cell phones and PDAs are typically worn on belts or kept in pockets, and need to be picked up and opened first before they can be accessed. Table 1 summarizes a study we did on various objects that people tend to carry with them. The study included about fifty researchers at IBM and technical visitors. As we see from Table 1, a wrist watch is a very attractive form factor into which one can pack a significant amount of computer power into. One of the reasons a wrist watch is attractive is that a large fraction of the population is already accustomed to wearing wrist watches. Further, people generally keep watches on their wrists, and watches are less likely to be misplaced compared to phones and pagers. For example, a hip holster is not the best place to keep a cellular phone while sitting in a car, and so people tend to keep them in the car seat and forget them when they leave the car in the parking lot. Another significant advantage of a wrist watch is that it is much more accessible than many of the other devices one may carry. It is often said that one of the reasons for the initial success of the Palm was its moving to an instant- on paradigm, i.e. eliminating the long boot up time associated with laptops. Wrist watches move us to the next step; to an instantly-viewable paradigm. The watch form factor requires a relatively small screen size, and there is not much room for input devices or batteries. The value of a wristwatch platform depends on finding good solutions to these issues. To interact with the watch, we need both hands since the hand on which the watch is worn is practically useless for controlling input devices on the watch, unless the hand wearing the watch is used to manip- ulate some other input device. Several smart watches are available commer- cially today. Personal Information Management (PIM) applications are provided on the Seiko Ruputer TM , the onHand PC TM , the Casio PC- Unite TM and the Timex DataLink TM . These watches pack an impressive amount of function but have low resolution displays. This limits the amount and type of data that can be displayed on their screens. The Casio WMP-1V TM is a wearable MP3 player, the Casio WQV-1 TM is a wearable digital camera, with a 1206120 dis- play, the Casio BP 100 TM measures blood pressure and the Casio Satellite Navi TM provides GPS on a watch. The Timex Beepwear TM watch has a built in pager. The Swatch Access TM watch has an RF id tag which can be used as a ski pass 17 # Springer-Verlag London Ltd Personal and Ubiquitous Computing (2002) 6:17–30