Vibrating Shoes Could Help the Visually Impaired Avoid Obstacles
John Simpson | August 04, 2016Researchers at the Massachusetts Institute of Technology are developing a boot with built-in sensors and “haptic” motors whose vibrations can guide the wearer around or over obstacles. Designed for people with compromised vision—such as spacesuit-clad astronauts or people with poor eyesight—the shoes' vibrations will move from low to high intensity when the wearer is at risk of colliding with an obstacle.Researchers are developing a boot with built-in sensors and “haptic” motors whose vibrations can help guide the wearer. Illustration: Jose-Luis Olivares/MIT
In a pilot study, Alison Gibson, a graduate student in aeronautics and astronautics, developed a device that spaced six haptic motors around each of a subject’s feet. One motor was placed each at the heel, big toe and instep, and three motors were placed along the foot’s outer edge. The intensity of the motors’ vibrations could be varied continuously between minimum and maximum settings.
A subject placed his or her feet in the device while seated before a computer and was asked to indicate when vibrations were felt and at what locations on the foot. Tests were conducted under two conditions. In the first, the subjects focused on the stimuli to their feet. In the second, they were distracted by a cognitive test: software would flash a random number on the computer screen, and the subject would count up from that number. The vibration of one of the motors would interrupt the counting, and the subject would report on the sensation.
The researchers had thought that variations in the intensity of the motors’ vibrations could be used to indicate distance to obstacles, as measured by sensors built into the boot. But they found that, when distracted by cognitive tests, subjects had difficulty identifying steady increases in intensity. And even when they were attending to the stimuli, subjects still had difficulty identifying decreases in intensity.
On the basis of the study results, Gibson is developing a boot with motors at three locations: the toe, heel and toward the front of the outside of the foot. Stimuli will not be varied continuously, but will jump from low to high intensity when the sensors detect a risk of collision. The high-intensity stimuli will also be pulsed, to help distinguish them.
In principle, the motor at the side of the foot could help guide the user around obstacles. But the first trial of the boot will focus on the problem of stepping over obstacles of different heights. The researchers will also be evaluating the haptic signals in conjunction with, and separately from, visual signals to determine the optimal method of conveying spatial information.