ISonar: an obstacle warning device for the totally blind

Abstract

Existing electronic travel aids have not been widely used by the visually impaired communities worldwide due to their low performance, unattractive appearance, impracticality, and high cost. This paper proposes iSonar – a miniaturized, high performance, and low cost obstacle warning device for those who are visually impaired. It was designed in accordance with the specific requirements of Thailand’s visually impaired users. To avoid collision, an ultrasonic transducer is used to detect obstacles by providing tactile feedback in different vibration frequencies at head and upper body levels; the coverage area is 130 cm in length and 80 cm in width. Our experiment compared performance between visually impaired volunteers’ standard white cane with and without our device. Fifteen visually impaired volunteers (nine males and six females) with total blindness, aged between 20 and 50 years (average age, 35.5 years), were enrolled from the Thailand Association of the Blind. Information and instructions on how to use iSonar, including device limitations, coverage area, and tactile feedback, were provided to users prior to commencing testing. Results found iSonar reduced the average collision rates by 26.66% (from 33.33% to 6.67%). iSonar also received a score of 4.13 rated as good–excellent on a Likert-scale from the visually impaired subjects. Keywords: visually impaired; obstacle detection; travel aid for visual impairments; ultrasonic transducer (Published: 11 June 2014) Citation: Journal of Assistive, Rehabilitative & Therapeutic Technologies 2014, 2 : 23114 - http://dx.doi.org/10.3402/jartt.v2.23114