INPUT TECHNOLOGIES AND TECHNIQUES
Ken Hinckley · 2007
What’s An Input Device Anyway? . . . . . . . . . . . . . . . . 162 Understanding Input Technologies . . . . . . . . . . . . . . 162 Input Device Properties . . . . . . . . . . . . . . . . . . . . . . . . 162 Property sensed . . . . . . . . . . . . . . . . . . . . . . . . . . . 162 Number of dimensions . . . . . . . . . . . . . . . . . . . . . 162 Indirect versus direct . . . . . . . . . . . . . . . . . . . . . . . 162 Device acquisition time . . . . . . . . . . . . . . . . . . . . . 162 Gain . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 162 Other metrics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 162 A Brief Tour of Pointing Devices . . . . . . . . . . . . . . . . . 163 Mice . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 163 Trackballs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 163 Isometric joysticks . . . . . . . . . . . . . . . . . . . . . . . . . 163 Isotonic joysticks . . . . . . . . . . . . . . . . . . . . . . . . . . 163 Indirect tablets . . . . . . . . . . . . . . . . . . . . . . . . . . . . 163 Touchpads . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 163 Touchscreens and pen-operated devices . . . . . . . . 163 Input Device States . . . . . . . . . . . . . . . . . . . . . . . . . . . 163 What’s an Input Device For? The Composition of User Tasks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 165 Elemental Tasks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 165 Compound Tasks and Chunking . . . . . . . . . . . . . . . . . 165 Evaluation and Analysis of Input Devices . . . . . . . . . 165 Fitts’ Law and Hick’s Law . . . . . . . . . . . . . . . . . . . . . . . 166 The Steering Law and Minimum Jerk Law . . . . . . . . . . 166 The Keystroke-Level Model (KLM) and GOMS Analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 166 Transfer Functions: How to Transform an Input Signal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 167 Self-centering devices . . . . . . . . . . . . . . . . . . . . . . . 167 Motion-sensing devices . . . . . . . . . . . . . . . . . . . . . 167 Absolute devices . . . . . . . . . . . . . . . . . . . . . . . . . . . 167 Feedback: What Happens in Response to an Input? . . 167 Proprioceptive and Kinesthetic Feedback . . . . . . . . . . 167 Kinesthetic Correspondence . . . . . . . . . . . . . . . . . . . . 167 Snapping Behaviors and Active Haptic Feedback . . . . 168 Keyboards and Text Entry . . . . . . . . . . . . . . . . . . . . . . 168 Procedural Memory . . . . . . . . . . . . . . . . . . . . . . . . . . . 168 Mobile Text Entry, Character Recognition, and Handwriting Recognition . . . . . . . . . . . . . . . . . . . 168 Modalities of Interaction . . . . . . . . . . . . . . . . . . . . . . . 169 Speech and Multimodal Input . . . . . . . . . . . . . . . . . . . 169 Bimanual Input . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 169 Pen and Gesture Input . . . . . . . . . . . . . . . . . . . . . . . . . 169 Whole Hand Input . . . . . . . . . . . . . . . . . . . . . . . . . . . . 170 Background Sensing Techniques . . . . . . . . . . . . . . . . . 170 Multitouch Tables and Screens . . . . . . . . . . . . . . . . . . . 171 A Society of Devices . . . . . . . . . . . . . . . . . . . . . . . . . . . 171 Current and Future Trends for Input . . . . . . . . . . . . . 171 References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 172 Input devices sense physical properties of people, places, or things. Yet any treatment of input devices without regard to the corresponding visual feedback is like trying to use a pen without paper. Small-screen devices with integrated sensors underscore the indivisibility of input and output. This chapter treats input technologies at the level of interaction techniques, which provide a way for users to accomplish tasks by combining input with appropriate feedback. An interaction designer must consider (a) the physical sensor, (b) the feedback presented to the user, (c) the ergonomic and industrial design of the device, and (d) the interplay between all of the interaction techniques supported by a system.