Exploring interaction with a simulated wrist-worn projection display

One of the major limitations of portable computing devices is the small size of their built-in displays. Fortunately, extremely small projection systems are being developed that can be integrated into devices that are small enough to be body-worn, yet can project a large image onto surfaces in the environment. To explore how a user might interact with this near-horizon technology, we created a functional simulation of a wrist-worn projector. We then developed a set of interaction techniques that assume that the wrist-worn computer and projector are equipped with position and orientation sensors, in addition to a touch-sensitive built-in screen. To complement the techniques that rely on the spatial manipulation of the user's forearm and the device itself, we also describe the use of a cursor less watch user interface that minimizes the need for the user to look down at the device's built-in screen. Finally, we present a sample application that illustrates our interaction techniques.