TWuiST: A Tactile-Proprioceptive Display for Eye and Ear Free Output
Interaction capabilities of mobile devices are typically restricted by their weight and size, which curbs their functionality, usability, and accessibility.
Whereas most research has focused on increasing available input space, we argue that output capabilities of mobile devices are also constrained, not only because of their small screens and limited audio capabilities, but because: (1) users often interact with their mobile devices when they are active and the use of a display or audio may impede the users' safety, for example, when they are walking or driving; (2) the use of audio feedback may be limited due to noisy environments and safety and privacy issues; and (3) users may be unable to use a screen because of a visual impairment. We propose a new eye-free interaction technique for mobile devices that utilizes proprioception, e.g., the human ability to sense the orientation of limbs without vision or hearing
How it works
We explore proprioception as an output modality by combining kinesthetic information of a mobile device with vibrotactile feedback. The user scans through different orientations (see image) of their mobile device where a specific target orientation is indicated using a vibrotactile cue. Different target orientations correspond to different types of information that the user can access in an ear and eye free manner. An example application of this technique could indicate the status of a mobile device where LEFT indicates a new email and RIGHT a missed call
A user study with 16 users explored the temporal resolution of proprioceptive displays for two different spatial resolutions with orientations either defined in a space or in a plane. Users were able to find target orientations in 2,466 (space) and 2,612 (plane) milliseconds. The performance of discrete proprioceptive displays is comparable with more advanced forms of tactile feedback provision -but unlike these- proprioceptive displays can be facilitated using features already present in current mobile devices.