Application of Shape Memory Alloy (SMA) Based Actuation for Refreshable Display of Braille

Persons with blindness access computers with the help of refreshable Braille displays and speech synthesis softwares. Braille has distinguished advantages over synthetic speech, especially because of its important role in uplifting education, employment and income. However, commercially available Braille displays are typically priced in the range of 2500-4000 USD (65-100 USD per Braille character) and are thus inaccessible to users in both developed and developing countries. Development of affordable Braille displays is thus a critical need. Shape Memory Alloy (SMA) based actuation is a potential low-cost alternative to currently employed piezoelectric actuation, and is being used here to develop an affordable Braille display. This paper discusses key challenges identified in SMA based actuation and proposes methods to overcome the same. Prior attempts at developing tactile displays employing SMA based actuation are reviewed and important considerations for the present study are drawn. The configuration and the design of the actuator are thus arrived at. This paper further discusses the performance of fabricated prototypes and the feedback received from limited user trials. It concludes with a discussion on future scope of the work.