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 goodexcellent on a Likert-scale from the visually impaired subjects.