Loughborough Papers

Talking Lights

William Loughborough
Research Notes
Journal of Visual Impairment and Blindness, 1979, June. 243

"Where am l?" was a cliche‚ in old movies, when the hero came to after being slipped a Mickey Finn or after being roughed-up by a bunch at hoodlums. For blind people, "Where am l?" can become a continuous drone, unless they become really expert in a wide range of skills usually grouped together as orientation and mobility. The area of mobility has had a lot of technological effort devoted to it, but the sighted guide, long cane and dog guide are still unapproachable in acceptance among visually impaired persons. And it is a curious anomaly that little research has been done concerning orientation, since for the experienced blind pedestrian the worst travel problems are not obstacle avoidance and path maintenance but avoiding the old, "Where am l?" cliche.

When we first began to think about how to help visually impaired persons remain oriented, we hoped that by using some elaborate software (computer programs) we could take advantage of the existing U S. Coast Guard Loran C network. In theory, this network of electronic beams can allow a person carrying an appropriate receiver to know where he is within about 20 ft -at best. But reception of the Loran beams might not be good in hilly cities, and even among certain buildings, and the network does not extend very far from coastal waters. Further, much required orientation information is on the far smaller scale of hotel room numbers, building directories, transit system guidance, and so on. Braille markers have been proposed but not all blind people read Braille and, a more serious problem, it is hard to find the Braille signs (except in elevators).

Two Technologies:

It becomes apparent that a new approach is needed to make independent orientation more widely available. The devices we propose meld two technologies: infrared communication (long neglected because of military secrecy) and synthetic speech, which involves small chips (integrated circuits) that can reliably and permanently store verbal messages long enough for many applications.

Infrared Light:

Infrared light is invisible to human eyes, though many animals use it in the same way we use visible light. Like ordinary light it can be transmitted, focused, spread and reflected. It is localized and therefore unlikely to interfere with other transmissions. This is an important consideration because to allow precise orientation, transmitters would nave to be fairly close together. In the system we have designed, the infrared light from a light emitting diode (LED's) -- a component frequently used for the visual display on calculators -modulated by the message in synthetic speech stored in an associated solid-state memory device with a read only memory (ROM). This signal can be detected by a portable receiver which when pointed approximately at the LED will deliver the message through a speaks or earphone.

The System's Potential:

When these talking lights become widely distributed the traveler with the talking-lights detector should be able to know what street he is on, find the appropriately marked corner for the bus stop and know which bus is approaching, and be able to tell if one of the cars going by is an available taxi. In the subway he or she would know where the ticket machine is, in a hotel he would know which hall leads to the correct hotel room. It would be easy to locate the entrance to the Social Security office, or where the Psychology 101 lecture has been transferred, if the structures were equipped with talking lights. At conventions attended by many visually impaired persons, the convention center or hotel could be appropriately marked with talking lights and the blind participant issued with receivers for the meeting's duration. In addition to building directories, a very short- range talking light could serve as a menu, a hearing aid in certain circumstances, or as a homing beacon for sports activities. After initial development and tooling, the cost will be low, the reliability and durability high, and the operating energy just a few cents worth of electricity each year. The battery life in the receiver depends on usage, but a year or more is not unlikely,

The System Now:

To date we have evolved the system to transmissions of frequency-modulated pulses of 950 nanometer light at around 25 KHz. The speech is compressed by a delta- modulator and stored in RAMs (random access memory) in the demonstration device. Programmable read-only memories (PROMS) will be used in the next generation but the receivers and transmitter will be basically as they are in the lab. The first test system will be several doorways, exits, elevator buttons, etc., on the fourth floor of the research building at the Smith-Kettlewell Institute of Visual Sciences. Further development should, we believe, be coordinated within one facility to avoid incompatibility in receivers and to most effectively develop a dependable, widely deployed network -- designed and operated by and for blind individuals.

This research has been funded in part by the Rehabilitation Services Administration. OHEW, Grant No. 23-P-57590/9-03.

Mr. Loughborough is an engineer in the Rehabilitation Engineering Center, Smith-Kettlewell Institute of Visual Sciences, San Francisco.


William Loughborough
The Smith-Kettlewell Eye Research Foundation
San Francisco, California

Presentation before the Pan Pacific Symposium
Vancouver, Canada, 1986


Talking Signs do for print- handicapped persons what printed signs do for those able to read them. They are small, inexpensive voice-modulated infrared transmitters whose message is heard by means of a pocket-size receiver which speaks the Signs' messages and indicates the direction of their source.

The Need:

Signage for blind and other print- handicapped persons is important for orientation and safety for example, in a typical subway the name of the station, location of attendant booth, turnstiles, platform edges, escalators and stairs are all essential for safe, independent travel. present methods require special accommodations--like a plea for help by the traveler ("Where am I?"). Although most everyone is willing (in fact, anxious) to offer help, such assistance is often erroneous, and occasionally dangerous. There is also special accommodation in fares, which may be seen as demeaning. Blind people in general eschew such special accommodation and would rather have a guidance system that functions to permit independent travel, such as is made available to sighted, literate users of the public transportation system. By supplementing printed signs with Talking Signs (Loughborough, 1979), we could enable non-reading travelers to become independent and escape the constant annoyance of well-intentioned misdirection.

"Talking Signs":

Each transmitter consists of a power source operating a modulated infrared light beam. The currently available commercial version is operated from AC power lines, but demonstration devices powered by light and/or batteries have been shown. As light- powered versions come on line, installation and maintenance will be as simple and inexpensive as for any signage. The voice is recorded on and stored in a silicon memory chip that permits a clear spoken message of from two to thirty seconds--depending on the capacity chosen. The recording is done on a simple device which permits modification of fixed signs. The receiver uses a sensitive light detector-demodulator with a speaker to say the message. It can be small enough to be carried in a pocket, loud enough to be understood in a subway, rugged enough to be tossed about or dropped, dependable enough to last years with only occasional battery changes, and inexpensive enough to be part of a practical solution to an annoying and dangerous problem.

Examples and Test Results:

Tests of the system's performance and utility have been undertaken at Smith-Kettlewell in San Francisco, San Diego Community College, Los Angeles' Braille Institute, and in Montreal and Paris. The transmitters have functioned reliably. They are very easy to locate and understand. It is instantly obvious to those trying them how useful they would be if widely installed. Formal testing has demonstrated that the speech intelligibility of the system is 98.7 percent for typical messages presented in random order to native English speakers, and does not differ significantly under these conditions from the intelligibility rate of similar messages presented on a high-fidelity tape recording system (Brabyn and Brabyn, 1982). Further tests comparing the time required by blind subjects to locate rooms in a typical building indicated that 71% of the subjects took less time to reach the target locations using the Talking Signs than using raised-print labels (Brabyn and Brabyn, 1983). User comments were extremely positive.

Reliability and effectiveness testing at two campuses of the San Diego Community College demonstrated that the system operates reliably both indoors and out, and is of assistance to new students in becoming oriented at the beginning of the school term. The installation was not subject to any vandalism, despite fears by security officers that the transmitters would all be removed within a week. The system works in dark and sunlit places. Building directories, shopping mall maps, traffic signals, and all other sign age could be made instantly usable (virtually no training necessary) for blind or illiterate people.

Economics and Implementation Issues:

In their current state the transmitters cost about $50 each, but large- scale production could render them as inexpensive as light bulbs. Installation costs are high, but when light powered versions are in production they will be installed (both indoors and outdoors) without breaking into the power grid. The receivers cost about $150 each. This figure would also be reduced by the economies of scale, although fewer receivers than transmitters will be required. Estimates for an elaborate subway station installation are about $30,000, using presently available devices. For $25, individual stores or residences could put in a real "lighthouse for the blind," even assuming only modest progress in reducing the system's cost.

The Talking Signs system does not have to be universally implemented before it can be of use. Model Talking Signs installations in even limited areas, which pose particularly extreme difficulties for the blind pedestrian, would easily justify their expense and would provide a base for expansion into other areas of the environment. For example, a Talking Signs installation within an underground subway system would in itself provide a quantum advance in safety and travel independence for the blind residents of the city. in time, it is hoped that a series of individual examples will lead to widespread availability of sign age usable by people who cannot read our conventional versions.


The Talking Signs, as outlined above, work to the same end as conventional sighted people's signs. They do not pollute the audible environment any more than would reading the signs aloud (and this occurs only during access). They are practically maintenance-free and negligibly expensive to operate. Some per-user economy is realized when account is taken of non-readers and other print- illiterates. The reaction of blind subjects and users who have been exposed to the Talking Signs has been overwhelmingly positive. Continued refinements in technology and cost reduction, along with a carefully phased implementation beginning with critical areas for accessibility, offer an opportunity for improved travel safety and independence for a significant proportion of our population.


Brabyn, J. and Brabyn, L. "Speech Intelligibility of the Talking Signs." Journal of Visual Impairment and Blindness, 1982, No. 76, pp 77-78.

Brabyn, L. and Brabyn, J. "An Evaluation of Talking Signs for the Blind." Human Factors, 1983, Vol. 25, No. 1, pp. 49-53.

Loughborough, W. "Talking Lights." Journal of Visual Impairment and Blindness, June 1979, p. 243.


The above research is supported by grants from the National Institute of Handicapped Research and The Smith-Kettlewell Eye Research Foundation.

Orientation: The Missing Factor in O&M

William B. Loughborough
The Smith-Kettlewell Eye Research Institute

Proceedings, California State University, Northridge
5th Annual Conference on
Contemporary Applications of Technology
Los Angeles, March 21-24, 1990, pp. 425-29.

Training in orientation and mobility for blind/visually impaired has historically been directed almost exclusively towards mobility, leaving orientation to discussions of methodologies for traversing rote paths. Without access to signage, the blind traveler in unfamiliar locales is forced into seeking help, reducing independence even further. Several pieces of legislation make the prospects for accessibility more than idle optimism and the possibility of signage usable by blind travelers is not the fantasy it once seemed. Talking Signs developed at Smith-Kettlewell over the past ten years provide a practical means for making orientation in public places feasible sooner through accessible addresses, phone booth and transit system locators, etc. Test installations at Smith-Kettlewell, San Francisco Lighthouse, and at a difficult intersection (1Oth & Market} will be simulated in this lecture/demonstration.

Orientation Observations:

Sighted travelers are in the main so accustomed to signage that they aren't aware of its importance, particularly when in a novel environment. We don't label the rooms in our houses, but to find one's bedroom in a hotel without labels would make us aware of the importance of floor numbers, door numbers, exit signs, warnings near elevators ("IN CASE OF FIRE., DO NOT USE ELEVATOR"} "Where is that stairway exit?'' comes to mind - and how do blind guys know about these things, they are excluded from exit aisle seats on airplanes on the pretext of overall safety. Signage is provided to preclude the constant need to ask directions, which is annoying to everyone concerned in most urban situations. If there's no one around to ask it gets even more trying, hence people lost in the woods. In many cases, blind travelers are that lost in cities where even the phone booths are systematically hidden from them.

Legislative Recourse:

Although the various regulations surrounding the accessibility laws have not to date included signage for the visually impaired, the intent of the underlying legislation makes it clear that this access is a matter of right, not privilege. The barrier compliance boards do not act on their own and recourse to litigation is at best uncomfortable, expensive, but usually effective. Acts of civil guerrilla activity have been useful in gaining access for mobility impaired transit system users, as well as in a few cases involving safety for the blind -- notably edge marking on subway platforms. Further legislation is in the works, but unless the regulating bodies are willing to enforce the intent of the law. In general. the battles should be fought with the agencies charged with enforcing existing laws rather than with the legislative bodies to pass more unenforced legislation.

Progress Towards Solution:

Ten years ago, engineers at Smith-Kettlewell Eye Research Institute began demonstrating a system to enable signage for the blind in the form of miniature infrared transmitters containing messages that duplicate visual signage in recorded form. In most ways they behave just like printed signs - they can be read from a distance they contain information essential to orientation, and they need not be read unless needed the system has been used indoors and out, far and near, in bright sunlight and rain and for several years of uninterrupted. reliable operation. They are inexpensive, easily installed. and provide the means of improving safety and independence for travelers who cannot, use visual signage. A demonstration system is being prepared for use at several conferences this summer that will continue to provide awareness and familiarity with the devices. A demonstration at 10th and Market in San Francisco is about to be installed and should provide a showcase that through media attention will make the system's development more rapid.


A group of blind travelers in San Francisco calling themselves SOBA (Society of Blind Administrators) has begun talking a more militant stance towards the problems facing them in independent travel. The traditional passivity of their community is fast disappearing. When this subject was first presented (In Washington. DC., Toronto, etc.) 8 - 10 years ago. the most frequent comment was "They will never let us have this'' or "This is too expensive. we could better use that money to get more jobs." There is no fixed pool of money that goes towards some chosen goal. There was no funding for curb cuts twenty years ago, yet billions of dollars were somehow spent on them. The efforts towards employment have shown some success (a lot less broom winders, and the top achievements are no longer running news stands or tuning pianos), but these efforts will not be reduced because signage becomes available. It doesn't do much good to get a job if you can't get to it using public transportation -- and self-esteem is certainly not enhanced by constantly being forced to ask "Where am I?" The answer to that is "You are here, and this now, and Now is the Time."