AirTouch: Synchronizing In-air Hand Gesture and On-body Tactile Feedback to Augment Mobile Gesture Interaction

We present the design and evaluation of Air Touch, a wristwatch interface that enables mobile gesture interaction through tactile feedback during limited visual attention conditions. Unlike its predecessor, the Gesture Watch, Air Touch is supported by a push-to-gesture mechanism (PTG) where the user performs a gesture and then confirms it afterward with a trigger gesture. The Gesture Watch, in contrast, requires the user to hold a trigger gesture while performing an interaction, and its PTG method does not allow the user to preview nor reverse the action. The effect of the new PTG mechanism and tactile feedback are evaluated through two experiments. The first experiment compares Air Touch's PTG mechanism to that of the Gesture Watch both with and without visual access to the watch. The second experiment examines mobile gesture interaction with the new PTG mechanism in four conditions (with and without tactile feedback and with and without visual restriction). We found that the new PTG mechanic enabled more accurate and faster interaction in the fully visible condition. Additionally, tactile feedback in the limited visual access condition successfully compensated for the lack of visual feedback, enabling similar performance times and perceived difficulties as in the fully visible condition without tactile feedback.