2004 Conference Proceedings

Go to previous article 
Go to next article 
Return to 2004 Table of Contents 


A REVIEW AND COMPARISON OF ELECTRONIC TRAVEL DEVICES FOR THE BLIND

Presenter(s)
William M. Penrod, Ed.D.
Teacher Preparation program,
Visual Impairments/Blindness, Orientation & Mobility,
Department of Teaching and Learning,
College of Education & Human Development, University of Louisville
Dept. of T&L, CEHD, University of Louisville
Louisville, Kentucky 40292
Phone: (502) 852-0557
Fax: (502) 852- 1419
Email: wpenrod@louisville.edu

Debra Bauder, Ed.D.
Assistive Technology Program,
Department of Teaching and Learning,
College of Education and Human Development, University of Louisville.
Dept. of T&L, CEHD, University of Louisville
Louisville, Kentucky 40292
Phone: (502) 852- 0564
Fax: (502) 852-1419
Email: bauder@louisville.edu

Thomas J. Simmons, Ph.D.
Department of Teaching and Learning,
College of Education and Human Development, University of Louisville.
Rm 158, Dept. of T&L, CEHD, University of Louisville
Louisville, Kentucky 40292
Phone: (502) 852- 0569
Fax: (502) 852-1419
Email: tsimmons@louisville.edu

During and before the 1970's much attention was given the notion that independent travel by persons who are blind who use a standard long cane or dog guide could be improved through the use of a new category of mobility system. Indeed, the electronic travel aid (ETA) or as many prefer the term electronic travel device (ETD), now offered the cane or dog guide user with extended knowledge of the environment which approached 4 meters, over twice the distance that one could gain knowledge of with a standard 54" long cane and an incalculable distance for a dog guide user.

ETAs may be described as devices that send out signals to sense the environment (preview) within a certain distance and inform the user of relevant bits of information about the environment forewarning the user about safety hazards that may lay ahead (Farmer, 1975). Blasch, Long, and Griffin-Shirley (1989) assert that such devices transform information about the environment which would normally be perceived through the visual sense into a form that can be perceived through another sense by the person who is blind. Usually, this information is transferred to the person who is blind through tactile/haptic, audition, or a combination of the two.

Miniguide

The Miniguide is a small ultrasonic ETA developed by GDP Research,. It is intended as a secondary device, only. It will not negate the need for a long cane or dog guide. It is available in two models, one audible and the other tactile.

Of great interest is the "watchdog" feature found on the audible model. This feature allows the device to be positioned toward an avenue of approach to give advance warning of someone entering the room and coming to within 2 meters of the user. In this particular mode battery life would be extended to over 400 hours of continuous use.

Also of interest is the number of modes or selections available to the user. Although the makers of the device indicate a total of twenty-three, they recommend that the novice user limit their selection to the first seven, the user may quickly wish to expand those options to the first nine, thereby taking advantage of the watchdog feature at two and one meter ranges, respectively. Frankly, beyond that, the modes become increasingly difficult and less important to the average user.

The first nine modes are 4-meter range, 2-meter range, 1-meter range, half-meter range, 4-meter range musical feedback, 2-meter range musical feedback, 1-meter range musical feedback, 2-meter range low-power watchdog, and 1-meter range low-power watchdog. Each mode/option is indicated by a single beep. Since the device automatically defaults to the 4-meter range when turned off, all the user must do is turn on the device and immediately release the button to be in the first mode, e.g., the 4-meter range. If another mode is desired the user simply does not release the button and counts the "beeps" until the desired mode/option is reached and then releases the button before the next "beep".

When walking under a blindfold it was noted that 1-meter and half-meter range modes seemed to offer the most confidence for the novice user. However other individuals may have other preferences. After a little practice one may quickly and accurately move through different modes/options as circumstances dictate. For example, for indoor travel one may find that the lower range modes are preferred while for outdoor travel, especially when looking for a landmark, the 4-meter mode will be the option desired.

Trial indicated the Audible Miniguide is a very adequate device for its intended purpose, to extend the preview capability of the user beyond what one could expect with a cane or dog guide, detect obstacles to the front and above the wrist, assist in orientation by determining landmarks, assist in alignment without making physical contact with walls being trailed, and also provides the additional advantage of detecting persons approaching one's personal space while in the watch dog mode. In addition, the device offers more battery life than most devices and the batteries are easy to change when needed. Indeed, if the battery is changed within ten minutes of removal, the user's settings are saved. If not, the device defaults to factory settings. The user should find that the Audible Miniguide does not produce obnoxious or offensive tones and are loud enough for only those persons in very close proximity (approximately 12-15 feet) to the device to hear them at all.

The Tactile Miniguide offers most of the same functions as the audible model. Obviously, those musical and amplitude modes available on the Audible model are removed as well as the Watchdog mode. This model appears to offer the same impressive characteristics as the audible mode while only slightly increasing in size because of the addition of an AAA battery used in the vibration component. Of particular importance to the user are the following observations.

First, the tactile component may be expected to wear out with 1-5 years of use. Second, the battery life of the device is decreased from the 400-hour expectancy to what you may expect from an AAA battery tasked with vibrating each and every time an object comes into range. The makers believe that one may expect this battery to last up to 50 hours with normal use before replacement is necessary. The good news is that the AAA battery is even easier to replace than the lithium coin-cell battery and a spare could easily be carried in the user's pocket.

Three, the vibration of the Tactile version of the Miniguide may not be easily discernible to persons with Diabetic Neuropathy or others while wearing gloves in cold weather. Those persons and circumstances may be better served with the Audible Miniguide .

Overall, the Miniguide in either the audible or tactile versions are viable and cost efficient ETAs for the person wishing increased protection and preview capability in addition to what the long cane or dog guide may provide. However, weather may partially restrict its use the same as any other electronic device.

Guideline Hand Guide

The Hand Guide is an obstacle detection device that uses infrared sensors to preview the environment at a distance of up to 4 feet. It comes complete with a wrist strap, two AA batteries, pocket or belt clip, and a screwdriver to change the batteries. It is produced by Guideline.

The Hand Guide has one range and one range only, 4 feet. It has two modes, audible and tactile. Modes may be selected by manipulating the single control switch located on the topside of the device. Simply move the switch forward to engage the tactile mode, to the center position to turn the device off, and to the back to engage the audible mode. The audible mode is a "chirping" sound that may be controlled for loudness by the user placing a finger over the sound hole located almost exactly opposite of the control switch. The frequency of the chirps is increased as the device comes closer to an object. The same is true with the vibrations when using the tactile mode. The audiotape is thorough and easy to understand and within a few minutes the user may install batteries and begin using the device.

This device may be used to detect persons approaching the user's personal space by simply laying the device on a desk pointed at the most likely avenue of approach while in the audible mode. In this manner the user may know whenever anyone comes within 4 feet.

Trial indicated that this device is efficient as a supplement to the long cane or a dog guide in both the tactile and auditory modes. The user may easily circumnavigate obstacles to the front as well as above the wrist, trail walls without making physical contact, and detect open doorways and hallways. However, because of its 4 foot range it has only limited utility for determining and using landmarks, the user must always consider weather when using outdoors because it is not waterproof, and close attention to battery life must be given because of limitations of AA batteries and the replacement procedure requires the use of a small screwdriver.

In summary, the Guideline Hand Guide is a useful tool for the user who wishes additional coverage and protection to what a long cane or dog guide may provide. With only a range of 4 feet, the determination of landmarks is not much increased over the exaggerated sweep of a long cane.

Conclusion

Although both devices have inherent advantages and disadvantages, it is difficult to say with certainty which device is better or offers the most value for the money. Indeed, that discussion may be argued for many years to come. While the Hand Guide is significantly less expensive, it has a very limited range and subsequently less utility. Also, because it uses an infrared beam, it will not reliably detect glass. Conversely, the Miniguide has much more utility, especially for determining landmarks, but it may be too complicated for many users in its present configuration. Perhaps eliminating several of the modes would make it more user friendly. Certainly battery life and ease of changing batteries are considerations, as well. The aspect of the vibratory element wearing out is a consideration mentioned by the makers of the Miniguide is very important, especially when the Hand Guide has an audible mode built in that could keep the device operational in the event of partial failure. The potential user must weigh options very carefully according to his or her individual needs.

References

Blasch, B.B, Long, R.G., & Griffin-Shirley, N. (1989). Results of a national survey of electronic travel aid use. Journal of Visual Impairment and Blindness, 83, 449- 453.

Farmer, L.W. (1975). Travel in adverse weather using electronic mobility guidance devices. New Outlook for the Blind, 69(10), 433-439, 451.

Farmer, L.W. (1980). Mobility devices. In R.L Welsch & B.B. Blasch (Eds.), Foundations of orientation and mobility (pp. 357-402). New York: American Foundation for the Blind.

Farmer, L.W., & Smith, D.L. (1997). Adaptive Technology. In B.B. Blasch, W.R. Wiener, & R.L. Welsch (Eds.), Foundations of Orientation and Mobility (2nd edition.), (pp. 231-257). New York: AFB Press


Go to previous article 
Go to next article 
Return to 2004 Table of Contents 
Return to Table of Proceedings


Reprinted with author(s) permission. Author(s) retain copyright.