Text entry tap accuracy and exploration of tilt controlled layered interaction on Smartwatches

Design of text entry on small screen devices, e.g. smartwatches, faces two related challenges: trading off a reasonably sized keyboard area against space to display the entered text and the concern over "fat fingers". This paper investigates tap accuracy and revisits layered interfaces to explore a novel layered text entry method. A two part user study identifies preferred typing and reading tilt angles and then investigates variants of a tilting layered keyboard against a standard layout. We show good typing speed (29 wpm) and very high accuracy on the standard layout - contradicting fears of fat-fingers limiting watch text-entry. User feedback is positive towards tilting interaction and we identify ∼14° tilt as a comfortable typing angle. However, layering resulted in slightly slower and more erroneous entry. The paper contributes new data on tilt angles and key offsets for smartwatch text entry and supporting evidence for the suitability of QWERTY on smartwatches.