Input technologies and techniques

What’s An Input Device Anyway? . . . . . . . . . . . . . . . . 162Understanding Input Technologies . . . . . . . . . . . . . . 162Input Device Properties . . . . . . . . . . . . . . . . . . . . . . . . 162Property sensed . . . . . . . . . . . . . . . . . . . . . . . . . . . 162Number of dimensions . . . . . . . . . . . . . . . . . . . . . 162Indirect versus direct . . . . . . . . . . . . . . . . . . . . . . . 162Device acquisition time . . . . . . . . . . . . . . . . . . . . . 162Gain . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 162Other metrics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 162A Brief Tour of Pointing Devices . . . . . . . . . . . . . . . . . 163Mice . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 163Trackballs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 163Isometric joysticks . . . . . . . . . . . . . . . . . . . . . . . . . 163Isotonic joysticks . . . . . . . . . . . . . . . . . . . . . . . . . . 163Indirect tablets . . . . . . . . . . . . . . . . . . . . . . . . . . . . 163Touchpads . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 163Touchscreens and pen-operated devices . . . . . . . . 163Input Device States . . . . . . . . . . . . . . . . . . . . . . . . . . . 163What’s an Input Device For? The Compositionof User Tasks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 165Elemental Tasks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 165Compound Tasks and Chunking . . . . . . . . . . . . . . . . . 165Evaluation and Analysis of Input Devices . . . . . . . . . 165Fitts’ Law and Hick’s Law . . . . . . . . . . . . . . . . . . . . . . . 166The Steering Law and Minimum Jerk Law . . . . . . . . . . 166The Keystroke-Level Model (KLM) andGOMS Analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 166Transfer Functions: How to Transforman Input Signal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 167Self-centering devices . . . . . . . . . . . . . . . . . . . . . . . 167Motion-sensing devices . . . . . . . . . . . . . . . . . . . . . 167Absolute devices . . . . . . . . . . . . . . . . . . . . . . . . . . . 167Feedback: What Happens in Response to an Input? . . 167Proprioceptive and Kinesthetic Feedback . . . . . . . . . . 167Kinesthetic Correspondence . . . . . . . . . . . . . . . . . . . . 167Snapping Behaviors and Active Haptic Feedback . . . . 168Keyboards and Text Entry . . . . . . . . . . . . . . . . . . . . . . 168Procedural Memory . . . . . . . . . . . . . . . . . . . . . . . . . . . 168Mobile Text Entry, Character Recognition,and Handwriting Recognition . . . . . . . . . . . . . . . . . . . 168Modalities of Interaction . . . . . . . . . . . . . . . . . . . . . . . 169Speech and Multimodal Input . . . . . . . . . . . . . . . . . . . 169Bimanual Input . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 169Pen and Gesture Input . . . . . . . . . . . . . . . . . . . . . . . . . 169Whole Hand Input . . . . . . . . . . . . . . . . . . . . . . . . . . . . 170Background Sensing Techniques . . . . . . . . . . . . . . . . . 170Multitouch Tables and Screens . . . . . . . . . . . . . . . . . . . 171A Society of Devices . . . . . . . . . . . . . . . . . . . . . . . . . . . 171Current and Future Trends for Input . . . . . . . . . . . . . 171References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 172Input 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.