A bidirectional vibrotactile communication system: tactual display design and attainable data rates

A series of experiments with a bidirectional vibrotactile communication system examined the effectiveness with which a person can receive and react to vibratory stimuli applied to the skin. In order to design an effectual tactual display, vibratory patterns that varied in duration and shape were presented on the 6×24 vibrotactile array of the Optacon, a portable electronic reading aid for the blind. In determining the maximal set of unambiguously discriminable tactual patterns, the results of the first experiment indicate that higher resolution, a larger element size, and larger interelement spacing are desirable, yet potentially conflicting, characteristics for a tactual display. In the second experiment, a maximum data rate of approximately 10 b/s was attained through the tactual channel of the fingertip using vibratory stimulation. The results indicate that low-resolution tactual displays are just as effective in transmitting information as tactual displays with a larger number of elements