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Wolfgang Fink, Bassil Ramadan, Andres Nuncio Zuniga, Nick Powers, Kristena Kay, Sunggye Hong; VISTATM: Visual Impairment Subtle Touch AidTM. Invest. Ophthalmol. Vis. Sci. 2021;62(8):3530.
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© ARVO (1962-2015); The Authors (2016-present)
To devise a low-tech, low-cost, robust, and minimally obtrusive navigational traveling aid - the Visual Impairment Subtle Touch Aid (VISTA) - for people with visual impairments by combining ultrasonic range detection with proportional vibrational output.
A navigational aid (Fig. 1) was devised using a sensing belt equipped with independent ultrasonic sensors (Ultrasonic HC-SR04 Distance Measuring Transducers) for distance measurements. The sensors were mounted using mobile clips to allow for user adjustability. The sensing belt was connected to a stimulation belt affixed to the ribcage. The stimulation belt used vibrating minidisc motors with vibration relating to (e.g., proportional to) the sensed distance between the belt wearer and surrounding obstacles. Each distance measuring sensor was connected to its assigned set of vibrating minidisc motors via its own Arduino Nano that performed the conversion of the sensed distance to motor vibrations. The proof-of-concept VISTA device was validated through preliminary testing on blindfolded, but fully sighted, persons and one blind person (all authors) in navigating a novel environment without any additional aids, such as a cane.
While scaling the vibrational strength seemed intuitive at first, the near-field "perception" proved insufficient. Through programming the vibrational output to pulse at different intervals depending on the distance from nearby obstacles, i.e., temporal pulsecoding or frequency encoding as opposed to amplitude encoding, the need for a differentiating output was met. In preliminary tests, the devised ultrasonic-sensor-equipped belt and vibration-actuator-equipped vibration belt combination (i.e., VISTA) was capable of informing users of surrounding obstacles in real time while navigating a hallway with several turns.
VISTA is currently limited to level environments, especially indoors: Curbs or stairs still pose significant issues to the user without training or supplementary aids, as these obstacles are below the sensor range and therefore not detected. Miniaturization of VISTA would allow a higher density of sensors on the belt. While certainly not intended as a replacement for the widely and successfully used cane, VISTA may serve as an additional, minimally obtrusive navigational travel aid for the visually impaired to augment the spatial experience of their environment.
This is a 2021 ARVO Annual Meeting abstract.
Functional schematic of Visual Impairment Subtle Touch AidTM (VISTATM)
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