Sensory substitution using tactile pin arrays: Human factors, technology and applications

Tactile arrays use a matrix of individually controllable elements to present spatial and temporal patterns of cutaneous information. Early devices of this type were in the field of sensory substitution to replace vision or hearing for users with a sensory impairment. Many advances have been made due to the appropriation of tactile displays for telerobotics and virtual reality, to represent physical contact with a remote or simulated environment. However, many of these have been limited to engineering prototypes. The recent commercial availability of affordable, portable tactile pin arrays has provided renewed impetus to apply the technology to sensory substitution applications. Lack of access to digitally stored data can prove a significant barrier to blind people seeking careers in numerate disciplines. Tactile displays could potentially provide a discrete and portable means of accessing graphical information in an intuitive non-visual manner. Results are presented from experiments on tactual perception related to understanding graphs and simple visualisations with a commercially available tactile array device. It was found that subjects could discriminate positive or negative line gradient to within ±4.7° of the horizontal, compared to ±3.25° for results with a force feedback mouse and ±2.42° with a raised paper representation.