Gestyboard BackTouch 1.0: Two-handed backside blind-typing on mobile touch-sensitive surfaces

This paper presents a new and innovative gesture-based textinput concept designed for high-performance blind-typing on mobile devices with a touch-sensitive surface on their back-side. This concept is based on the Gestyboard concept which has been developed by the Technische Universität München for stationary use on larger multi-touch devices like tabletop surfaces. Our new mobile concept enables the user to type text on a tablet device while holding it in both hands, such as the thumbs are in the front of the tablet and the other eight fingers are in the back. The user can hence type text using these fingers on the back of the device. Although, the gesture-based finger movements are quite unfamiliar and the participants need to mentally rotate the QWERTY layout by -90 and 90 degrees respectively, our multi-session evaluation shows that despite the fact that their fingers are occluded by the tablet, our concept enables the users to blind-type and that they improve their performance in each session. Consequently, the user can use all ten fingers simultaneously to type text on a mobile touchscreen device while holding it comfortably in both hands. This implies that our concept has a high potential to yield to an high-performance text-input concept for mobile devices in the near future.