Abstract
The mobile phone is the first truly pervasive computer. In addition to its core communications functionality, it is increasingly used for interaction with the physical world. This chapter examines the design space of input techniques using established desktop taxonomies and design spaces to provide an indepth discussion of existing interaction techniques. A new five-part spatial classification is proposed for ubiquitous mobile phone interaction tasks discussed in our survey. It includes supported subtasks (position, orient, and selection), dimensionality, relative vs. absolute movement, interaction style (direct vs. indirect), and feedback from the environment (continuous vs. discrete). Key design considerations are identified for deploying these interaction techniques in real-world applications. Our analysis aims to inspire and inform the design of future smart phone interaction techniques.
Key Terms in this Chapter
Design Space: Design spaces provide a formal or semiformal way of describing and classifying entities along different dimensions, each listing relevant categories or criteria.
Indirect Interaction: User activity and feedback occur in disjoint spaces, where scaling and abstraction between input actions and feedback are often necessary.
Direct Interaction: Input actions are physically coupled with the user-perceivable entity being manipulated (such as an image on a display). To the user, this appears as if there is no mediation, translation, or adaptation between input and output. Physical coupling can be achieved when the feedback spatially coincides with the input action, or at a distance if the user is manipulating a 3-D ray (such as with a laser pointer) that intersects directly with the entity being manipulated.
Continuous Interaction: Interactions with a closed-loop feedback, where the user continuously gets informed of the interaction progress as the task is being performed.
Input Technique: A specific way of providing data input to a computer through a combination of input devices and software for visual, auditory, or haptic feedback.
Discrete Interaction: Interactions with an open-loop feedback, where the user is only informed of the interaction progress after the task is complete.