Investigating New Forms of Single-handed Physical Phone Interaction with Finger Dexterity

Abstract

With phones becoming more powerful and such an essential part of our lives, manufacturers are creating new device forms and interactions to better support even more diverse functions. A common goal is to enable a larger input space and expand the input vocabulary using new physical phone interactions other than touchscreen input. This thesis explores how utilizing our hand and finger dexterity can expand physical phone interactions. To understand how we can physically manipulate a phone using the fine motor skills of finger, we identify and evaluate single-handed "dexterous gestures". Four manipulations are defined: shift, spin (yaw axis), rotate (roll axis) and flip (pitch axis), with a formative survey showing all except flip have been performed for various reasons. A controlled experiment examines the speed, behaviour, and preference of manipulations in the form of dexterous gestures, by considering two directions and two movement magnitudes. Using a heuristic recognizer for spin, rotate, and flip, a one-week usability experiment finds increased practice and familiarity improve the speed and comfort of dexterous gestures. With the confirmation that users can loosen their grip and perform gestures with finger dexterity, we investigate the performance of one-handed touch input on the side of a mobile phone. An experiment examines grip change and subjective preference when reaching for side targets using different fingers. Two following experiments examine taps and flicks using the thumb and index finger in a new two-dimensional input space. We simulate a side-touch sensor with a combination of capacitive sensing and motion tracking to distinguish touches on the lower, middle, or upper edges. We further focus on physical phone interaction with a new phone form factor by exploring and evaluating single-handed folding interactions suitable for "modern flip phones": smartphones with a bendable full screen touch display. Three categories of interactions are identified: only-fold, touch-enhanced fold, and fold-enhanced touch; in which gestures are created using fold direction, fold magnitude, and touch position. A prototype evaluation device is built to resemble current flip phones, but with a modified spring system to enable folding in both directions. A study investigates performance and preference for 30 fold gestures, revealing which are most promising. Overall, our exploration shows that users can loosen their grip to physically interact with phones in new ways, and these interactions could be practically integrated into daily phone applications.