ThumbStroke

Abstract

The QWERTY keyboard on mobile devices usually requires users’ full visual attention and both hands, which is not always possible. We propose a thumb-stroke-based keyboard, ThumbStroke, to support both sight-free and one-handed text entry. Text entry via ThumbStroke completely relies on the directions of thumb strokes at any place on the screen of a mobile device. It does not require physical press on any specific keys, thus eliminating the need for visual attention and reducing errors due to tiny key size, fat thumbs, limited thumb reachability, and visual occlusion. We empirically evaluated ThumbStroke through a 20-session longitudinal controlled lab experiment. ThumbStroke shows advantages in typing accuracy and user perceptions in comparison to the Escape and QWERTY keyboards and results in faster typing speed than QWERTY in sight-free and one-handed text entry. This study provides novel research contributions to mobile HCI, advancing the design of soft keyboards for one-handed interaction with mobile devices and mobile accessibility.