A low duration vibro-tactile representation of Braille characters

Braille is a tactile writing/reading system used by people who are visually impaired. Traditionally, Braille has been used on static surfaces like books, signs or keypads, refreshable Braille displays are also available to be used as an interface for digital devices. The linear Braille alphabet proposed in this paper is a novel method to represent Braille characters using the vibration engine of a mobile device operated via vibro-tactile signal sequences. The standard vibration engine is driven to generate different haptic effects on the mobile device in a predefined sequence. Two different tests for distinguishing distinct sequences and characters were conducted over a subject group of 50 clear sighted people. Result of this test show that; signal distinguishability of the method is 99%, and character distinguishability is 97%, while maximum duration for a single character is 1050 ms. A second test on 10 visually impaired users presented a signal distinguishability result of 90% and a character distinguishability result of 82.5%. The method proposed in this paper shows promising results for representing Braille characters on a standard mobile device.