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ALEXANDER DEANS; iAid: Ultrasonic and GPS controlled Joystick Mobility Device. Invest. Ophthalmol. Vis. Sci. 2017;58(8):3288.
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© ARVO (1962-2015); The Authors (2016-present)
Currently, visually impaired persons rely on white guide canes for guidance. A more precise and effective mobility aid with precise tactile feedback using an omnidirectional toggle system linked to a portable ultrasound mapping device with GPS guidance was devised to improve navigation.
A novel, user-worn device (iAid) was devised using an Arduino microprocessor and Android platform. Outdoor navigation was facilitated by a GPS/ compass controlled joystick, which tilted to indicate distance and rotated to show direction to the destination. Waypoints were determined using Google Maps Directions API. Four ultrasonic belt-mounted sensors scanned a horizontal 90° field, and obstacles within 60 cm triggered a high frequency piezo buzzer. Indoors, belt-mounted sensors rotated the joystick to show the most open path. The data was compared to navigating unaided and with the aid of a guide cane . Volunteers (n = 20) were tested on an indoor course with various doorways and obstacles. The time to complete the course and the number of collisions was recorded for each of the following: blind, blind with guide cane, and blind with iAid. The outdoor system was tested by driving a car through multiple courses with waypoints, simulating a pedestrian’s path. This had the advantage of rapid testing of 23 different courses ranging from 400m to 6 km.
An 80% reduction in collisions ( p<0.01) was observed when using the iAid (21.5 ± 12.6), versus blind volunteers( 103.4 ± 16.6) or 43.8 ± 11.9 collisions using a guide cane (p < 0.01) . Overall, iAid users completed the course in 123.1 ± 4.4 seconds , requiring 57% of the time (p<0.001) compared to navigating blindfolded( 214.5 ± 49 s) and in 79% of the time (p<0.001) required with a cane (156 ± 4.2 s). The 23 different outdoor destinations were tested with a round trip to simulate the intended use of the device. All routes were completed successfully, with no misdirections. The iAid was able to guide the user to a previously unknown outdoor destination.
The iAid, which uses phone-based multimodal feedback, improves navigation by reducing collisions and increasing speed and safety versus using a cane and navigating unaided. It shows that a combination of tactile and auditory feedback is an effective way to improve navigation.
This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.
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