Main content

Alert message

Currently available
Design considerations
ETA Patents

An Electronic Travel Aid (ETA) is a form of assistive technology having the purpose of enhancing mobility for the blind pedestrian. Perhaps the most widely known device is the LaserCane, which is a regular long cane with a built-in laser ranging system. The Mowat Sensor is an example of a pocket-sized device containing an ultrasonic air sonar system. When it detects an obstacle, the device vibrates, thereby signaling the user. The research problem of designing a better ETA is a tough one. Despite 50 years of effort, no one has been able to design an electronic device that can replace the long cane.

Blind individuals find traveling difficult and hazardous because they cannot easily determine "where" things are, a process otherwise known as "spatial sensing." Thus the problem of mobility can be reframed as a problem in spatial sensing. The techniques for spatial sensing are well known, radar, sonar, and optical triangulation methods being the most common, and the latter two have been incorporated into a wide variety of past ETA designs.

However, there are many problems with currently available devices. First, the rangefinder technology is unreliable in its detection of step-downs or step-ups, such as curbs. Secondly, blind users find the sounds of various pitches or tactile vibrations being used to code the spatial information to be esoteric and difficult to understand. Thirdly, most blind users do not find the slight improvement in mobility performance to be worth the extra cost (which can be many thousands of dollars), and the additional worry of maintaining a complex, expensive battery operated system that must be carried around and kept track of.

I have been trying to design a more effective ETA for many years. Some have said that my Ultrasonic Spatial Sensing Aid, is the best attempt so far at recreating the experience of echolocation, as found in bats or dolphins. Yet it is far from perfected. In my design, ultrasound is radiated out and the returning ultrasonic echos are translated back down into the audible domain and presented binaurally to the blind user. The time based cues responsible for spatial hearing are encoded upon the sound, thereby creating the illusion of an externalized auditory image located out in space at the detected object's position. While my approach has promise, one of the significant drawbacks is that the user must wear earphones, which can interfere with the listening of normal environmental sounds.

More recently, I have been trying to commercialize a low-cost "electronic cane" similar in concept to the Mowat sensor. One blind person here in Hawaii says my invention is the best ETA he has ever tried and says he would gladly trade his own for mine. My device could be affordable, perhaps retailing for $50. My estimate is based on devices of similar complexity being sold at Radio Shack. What I need right now is assistance or advice (technical, financial, manufacturing, marketing, licensing), to bring this project beyond the prototype stage. If anyone can lend me a hand, please drop me a line by clicking on the address below. Last updated 11 October 1996

Copyright © 1996 by Duen Hsi Yen, All rights reserved.


Return to the wordmap.
about wordmap