Cyber Crumbs: An Indoor Orientation and Wayfinding Infrastructure

RESNA 28th Annual Conference - Atlanta, Georgia

David A. Ross, M.S.E.E., M.Ed.
Atlanta VA Rehab R&D Center
Decatur , GA 30033

Valerie L. Henderson, B.S.
Georgia Institute of Technology
Atlanta, GA 30018


An infrastructure comprised of prototype Cyber Crumbs was developed and evaluated in an NIH SBIR Phase 1 study. The goal was to develop a means of “salting” indoor structures with a network of inexpensive information “crumbs” to assist persons in easily orientating to indoor structures and efficiently navigating through them to desired locations. Infra-Red (IR) communications between Crumbs and a User Badge provide a channel for obtaining information. A low-profile bone-conduction headset provides voiced output of information. Seventeen visually impaired participants tested this system and showed significant improvements in navigation efficiency as compared with the performance of ten sighted participants. Performance measures included time and distance to reach specific locations.


Vision Loss, blindness, orientation and mobility (O&M), wayfinding


There are approximately 11.4 million people experiencing vision loss in the United States, ten percent of whom have no usable vision; and by 2010 these numbers will nearly double (1). Spatial orientation is the major mobility problem encountered by individuals with severe vision loss (2 ) . Spatial orientation is distinctly different from mobility in that mobility depends on skillfully coordinating actions to avoid obstacles in the immediate path, whereas spatial orientation refers to the coordination of actions to establish and maintain an awareness of one's position in space relative to landmarks in the farther-ranging surroundings and relative to a desired destination (3). Wayfinding is the ability to move to a desired destination using whatever spatial orientation cues are available. In this regard, the tendency to veer from a straight path is a major problem (4). The ability to obtain a tactile map, or audio descriptions, of a particular location prior to attempting a new route can be quite useful, but may require an excellent memory to faithfully and successfully follow routes with more than a few turns (5). Orientation and wayfinding cues placed along a route at critical travel points, however, can be most useful and not require an excellent memory to successfully and easily complete a complicated set of directions. As the majority of visually impaired persons are now aging adults over the age of 65, this can be a significant factor.

The Global Positioning System (GPS) is now used in a number of orientation and wayfinding aids for this very reason—it can provide in situ information on demand. However, GPS is useless indoors. Further, the one commercially available system developed for indoor orientation, Talking Signs®, has not been widely deployed despite the fact that it has been available for 20 years. The authors suspect that the cost of installation to building owners has been the major deterrent to widespread use of this system; and that if an inexpensive, easily installed, maintenance-free system were available, then acceptance and installation in public buildings would become more likely. Further, if this same infrastructure could be used to provide building security, then it might actually be sought out by building owners.

The above was the impetus behind the development of Cyber Crumbs, and used to establish design goals. For people with a visual impairment it would be an inexpensive infrastructure capable of providing needed orientation and wayfinding cues at needed in situ locations. For building owners, Cyber Crumbs would provide an alternative to the invasion of privacy that a network of video cameras and recorders imposes on everyone who might enter a building. In addition, Cyber Crumb security could provide full building coverage with less expense and maintenance than a comparable network of cameras and recorders. And in terms of privacy, unless a person does something that matches a suspicious pattern of activity, there would be no need to record their identity in any form.


When compared with the best possible scenario of having a highly experienced O&M instructor providing orientation and wayfinding directions just prior to navigating an unfamiliar indoor route, visually impaired persons using the Cyber Crumbs prototype infrastructure will perform significantly better in terms of completing an unfamiliar indoor route easily and efficiently.


Cyber Crumbs is conceived as an electronic “trail of breadcrumbs” that can be placed along specific routes through buildings. Upon entering a building, the person uses an information kiosk to select a desired destination, or destinations. This kiosk computes the simplest route to each chosen destination and downloads the route directions to the person’s User Badge in the form of an ordered sequence of Cyber Crumb ID numbers, and a set of directions that reference the physical landmark associated with each Cyber Crumb. The person can then listen to these directions in whole, or in part, at any time to better orient themselves to the route they are walking. Further, the User Badge automatically voices the name of each landmark when it is encountered along with route directions associated with that landmark. (e.g., “Hallway B intersection. Turn Right”). The information kiosk, itself, is the first Crumb in the route, and from this first Crumb the person is given directions to the second Crumb, and then the third, etc., until they reach their destination (the final Crumb in the route).

Unlike Talking Signs®, Cyber Crumbs store and transmit text information, not recorded speech. This makes it possible to transmit a large amount of information in a very short period of time, and for the User Badge to select only relevant pieces of that information for presentation to the person. The current Crumb prototype is built on a 2 by 3-inch circuit board (see Photo 1). To meet the above specified needs, including minimizing cost, Crumbs will only be placed at critical junctures along each possible path through a building (e.g., hallway intersections, transition points, stairways, elevators, escalators, entrances, exits, etc.), and at destination points (i.e., office doors, rest room doors, water fountains, etc.). To eliminate maintenance costs (e.g., changing batteries), a low-energy solar-powered design is being developed. Once perfected, the Crumbs will lie dormant absorbing light energy until a person needing their assistance comes along. When a person does come along, a signal transmitted once a second from the User Badge (see Photo 1) will then “wake up” the Crumb from a distance of up to 12 feet, prompting the Crumb to transmit it’s stored information once a second until the person is out of range, at which time the Crumb would “go back to sleep.”

Photo 1: Picture of Initial Cyber Crumb Prototype in Operation. (Click image for larger view)

The badge contains a voice synthesizer that voices relevant text from each transmitted message, and despite the repeated transmission of information from each Crumb, will only voice this information once, unless a repeat button on the badge is pushed. To prevent the masking of important audio cues from the environment, a low-profile bone-conduction headset, which does not cover the ears, is used to present information to the person. In the current version, Crumbs simply transmit their ID number and the name of the landmark to which they are attached (e.g., ID00213-David’s Office). Other information, such as a description of the surrounding building structure, will be included and tested in a future version.

The Cyber Crumb prototype was evaluated by 17 visually impaired persons ranging in visual function between profound vision loss and total blindness. Their performance in travelling unfamiliar routes was compared with 10 normally-sighted persons. Two comparable routes were used, each 200 feet in length. These routes were randomly selected as either a baseline or Cyber Crumb route for each participant. Prior to walking the baseline route a highly experienced O&M instructor gave the person verbal directions. Prior to walking the Cyber Crumb route the person was given 5 minutes of Cyber Crumb training. Measures taken were route walking time and actual distance walked. After using the system, participants were asked to rate its usefulness to them on a scale from 1 to 10.


Baseline-prototype differences in performance times and distances walked were quite significant, as compared with sighted participants (see Table 1). As shown, when using the prototype average performance times decreased from 3.9 times that of sighted persons to just 2 times, and distances walked decreased from 73% more than that of sighted persons to just 8% more. Together, these results show a very significant increase in route walking efficiency when using the Cyber Crumb system. Finally, the average usefulness rating was 8.33 out of a perfect score of 10, and all participant comments expressed enthusiasm for the system.

Table 1: Descriptive Statistics of Objective and Subjective Results
Measure N Mean Std. Dev. Minimum Maximum Significance (2-tailed)
Baseline Performance Time ¸ Sighted Time
Prototype Performance Time ¸ Sighted Time
Baseline Distance ¸ Sighted Distance
Prototype Distance ¸ Sighted Distance
Usefulness Rating ( Out of 10)


Investigators were very encouraged by these results and have written a Phase 2 proposal to further develop the system as a marketable product.


  1. Goodrich G. (1997) Growth in a Shrinking Population: 1995-2010. Palo Alto Health Care System. Palo Alto, CA.
  2. LaGrow S. & Weessies M. (1994) Orientation and Mobility: Techniques for Independence. Royal New Zealand Foundation for the Blind, Dunmore Press, pp. 9-30.
  3. Guth D. & Rieser J. (1997) Perception and the control of locomotion by blind and visually impaired pedestrians. Foundations of Orientation and Mobility, (Second Edition), AFB Press, pp. 9-38.
  4. Rouse D. & Worchel D. (1955) Veering tendency in the blind. New Outlook for the Blind, 49, 115-119.
  5. Blasch BB. (1991) Environmental Information Needs for Wayfinding by Special Populations. Final Report, VA Rehab R&D Project #E-561RA, pp. 7-8.


This study was funded by National Institute of Health grant # 1 R43 EY014747-01.

 Author Contact Information:

David A. Ross, MSEE
Atlanta VA Rehab R&D Center
MS 151R, 1670 Clairmont Rd.
Decatur, GA 30033
Phone (404) 321-6111 x6817