An electro-tactile display can be used to stimulate sensations in the skin. The ultimate achievement in this area is to open a new information communication channel using this sensory substitution system. One of the requirement of such communication channel is to deliver meaningful commands to the user. The sensations should be distinctive enough to be readily understandable for the operator.
This study is perusing the feasibility of generating identifiable moving patterns in the electro-tactile display. Then, the degree of identification performed by the users will be validated.
An electro-tactile display is built using an array of sixteen contacts to form a moving pattern by delivering electrical signal to the fingertip skin.
This signal can have varying voltages, frequencies or duty cycles to form the most comfortable sensation.
Moving patterns can be generated by individually or collectively toggling the electrical contacts on the electro-tactile display. This will achieve a stimulation of a moving pattern. In this regard, a moving pattern can be compared to a set of frame-by-frame pictures that construct a movie. Similarly, by toggling the contacts in a specific order, a moving pattern can be achieved.
In this study, eight subjects participated. A questionnaire was used to assess the sensation of the corresponding movement.
The results of these reports were analyzed and a conclusion regarding the identification of the direction of the movement was drawn. It became clear that the direction of the movement had a significant impact on the recognition of the patterns.
Furthermore, an analysis of the detection threshold (DT) voltage and current mapping was performed to evaluate the effect of the internal structure of the skin for each user on the assessment performance.
Based on the mapping results, it became clear that the DT voltage is vastly different for each contact and the resulting spatial map is also unique to each user.