Hands-free reading Braille with a vibrotactile wristband

In this paper, a new approach to display Braille is presented. Braille dots are mapped to six tactors of a vibrotactile wristband. The dot patterns of characters are displayed with adequate vibrotactile stimuli generated by the tactors. Compared to the conventional way of reading Braille, the advantage of the proposed approach is that there is no need to commit a hand to active Braille dot scanning and thus, the hand is still free for other activities or tasks. In a user study, different methods of mapping Braille to the wristband with respect to the assignment of cell dots to tactors as well as temporal aspects were evaluated using objective performance data and subjective ratings. Even with little training, promising results were obtained. Sequential mapping methods performed better than parallel methods and characters could be correctly recognized in up to 97% of cases.