Brandon Cox, a staff member at the nonprofit Columbia Lighthouse for the Blind, says inventors and marketers have approached him many times with what they think are wonderful devices to help the visually impaired become more mobile.

“It’s just crazy,” he says. “You’ve got eyeglasses that vibrate when you get too close to something. You have smart canes that give you everything from the weather to vibrations for whatever’s in front of you. I mean, there’s a camera you wear on your forehead, with an earpiece, and there’s somebody sitting on the other end, telling you where to go.”

The promoters often want financial help and endorsements from the CLB, as the organization is known. But Cox, the group’s senior director of education and rehabilitation services in Washington, typically says no, citing cost concerns.

“Only one percent of the population is visually impaired,” he says. “A market like that just isn’t going to sustain any kind of expensive product.”

That’s why he is excited, he says, about the debut of a product that not only will be free, but also is the first of its kind: a Web site and smartphone app designed to help blind people navigate in Metrorail stations, which can be treacherous places for the sightless.

Two years in the making — a collaboration between CLB and a St. Paul, Minn., company called ClickAndGo Wayfinding Maps — the Web site is set to be launched Friday, with the app soon to follow. Initially, the service will offer information about one station, Gallery Place-Chinatown. But within a few years, depending on the availability of grant money, Cox says, it could expand to the rest of the subway system.

“We want Washington, D.C., to become a model for this program,” he says, “We want to encourage other transit systems to implement it in their locations.”

On the Web site, www.clb.org/clickandgo, and the app, a user will find four types of information about Gallery Place (and eventually all 91 Metrorail stations, Cox hopes), including a high-resolution­ map of the station’s interior for people with limited vision, a detailed audio description of the station’s layout and a list of points of interest in and around the station, which has three entrances near Verizon Center.

The main feature, though, is audio walking directions. As with the audio information about the station layout and points of interest, the walking directions will be available through the app or in files that can be downloaded from the Web site. There are 105 sets of directions, from train platforms to bus stops and myriad other combinations, Cox says.

Patrick Sheehan, chairman of Metro’s volunteer Accessibility Advisory Committee, says he tested the service recently and found it to be “very, very good.”

“Gallery Place is a station I’m not familiar with and actually a station I avoid,” says Sheehan, who is blind. “And I was able to take the directions and do a nice job of getting off the train and navigating my entire route.” He was headed to Metro’s headquarters, a few blocks from the station. “The directions were very precise. You take a left; you go across the street; you find a certain wall with your cane. It has all that kind of stuff.”

Metro says it does not know how many blind people regularly use the subway system. But nearly 3,000 visually impaired commuters are eligible to use MetroAccess­, the van service for people with disabilities. If the new service prompts some of them to switch from MetroAccess to Metrorail, it would save money for the transit agency.

In 2011, Cox says, he and Brigid Doherty, an “orientation and mobility specialist” for Metro, obtained a $100,000 federal grant to develop audio maps of Metrorail stations.

Then, in 2012, Cox was talking about the project with a professor of blindness and low-vision studies at Western Michigan University. “And he said to me, ‘This kind of technology already exists.’ He said, ‘Have you ever met Joe Cioffi?’ ”

Cioffi, whom Cox had never heard of, is the founder of ClickAndGo Wayfinding Maps, which by then had developed narrative mapping products for colleges and public buildings around the country. Cox and Doherty teamed up with Cioffi, using the $100,000 federal grant to create the Web site and app.

Cox says they started with Gallery Place-Chinatown because “it’s a very complicated station,” with two levels, three subway lines, a relatively labyrinthine layout and a high volume of passenger traffic. He says the station will serve “as a demonstration of how this works” while CLB seeks more grants to expand the service.

“It’s not $100,000 per station,” he says. “The money went into building the methodology. I would say, in general, you could see a larger station, like Metro Center, costing up to maybe $50,000, and smaller stations could be $10,000 to $20,000 each.”

Using grant money that’s already available, Cox says, Cioffi’s company will expand the database early next year to include audio descriptions of 10 other stations: Metro Center, L’Enfant Plaza, Fort Totten, Rosslyn, Silver Spring, Dupont Circle, Anacostia, Columbia Heights, New Carrollton and Navy Yard-Ballpark. Additional features, including walking directions, will depend on future funding, he says.

“I’m always skeptical of any kind of blind technology,” Cox says. “People show up here with $4,000 smart canes they’ve invented, when the population we serve, over 70 percent of them are unemployed. They can’t afford expensive devices.”