New York: A University of Rochester faculty member and his students have created a unique system that will enable a visually impaired person to determine his whereabouts with the help of radio signals.

Nicknamed "NAVI" for Navigational Assistance for the Visually Impaired, the radio signal-based device can gauge when someone is near passive transponders as small as a grain of rice and located on the outside of a building, on a specific door inside, or on a painting or object of interest.

"This is a wonderful example of our students taking theory from the classroom, knowledge of some of the difficulties faced by some groups of people, and combining that with existing devices to transform it into a real world application that is of genuine usefulness to people," says Jack Mottley, associate professor of electrical and computer engineering and biomedical engineering.

According to Mottley, the system is an improvement on the security tags that are frequently used at retail stores or gasoline stations. While security tags at these places tended to set off an alarm after a sale, Mottley's engineering students decided to make the reader portable and affix the tags to stationary objects, like buildings.

This enabled the system to use the encoded information as an assistance device for the blind.

They built a piece of equipment that was essentially a portable detector coupled to an audio playback device. Connecting a portable CD player to the device, the students programmed it to play a particular track through an earphone whenever a certain tag was detected.

It could be a simplistic message such as, "Mr. Smith's office door", to an elaborate discussion of a piece of art in a museum, or the history of a building on a self-guided campus tour.

The students predict that improvements of the device could store information in solid-state memory that could be updated automatically when entering a new building, or allow a person to lay out her own tags and record relevant information for each.

Built of off-the-shelf components, the NAVI device currently is a black box about half the size of a loaf of bread, with a portable CD player and an antenna that looks like a singer's microphone.

A final version would probably be as small as a portable CD player, and if solid state memory like those in today's popular MP3 players were incorporated, the entire device may be no larger than a deck of cards.

"To prepare a building or site for use with this system will be relatively inexpensive. The tags are inexpensive now and the prices are still dropping. The plan is to use only passive tags that do not require batteries or need to be plugged in, meaning once they are installed they can be ignored," Mottley says.

In the far future, a NAVI system may find uses well beyond helping the visually impaired navigate their surroundings. Such a personal identifier might be built into cell phones or wrist-watches, allowing someone to gain information on almost anything around them, from customer reviews about a shirt they're considering buying, to paying for a soda at a vending machine.

Mottley and his students are applying for their patent, with the aim of enlisting the aid of a manufacturer to make the system as user-friendly for the visually impaired as possible. They hope to have the system integrated into a new building on the university campus being designed especially for biomedical engineering, as well as to be included in a large-scale upgrade of signage and markings that has been planned for the university.

ANI