While getting one of his checkups at the Mayo Clinic for a condition that has left him legally blind, Sydney Simon realized how helpful it would be if passersby knew he might need assistance.

And always thinking like a businessman -- after all, 43 years ago he founded the Original Hot Dog Shop, which has become a Pittsburgh institution -- he came up with an idea for clothing he calls Blindwear.

It includes a line of caps, T-shirts, sweat and polo shirts imprinted with the words "Blind. Please lend a helping hand.'' Similar low-vision wear is available, and he plans to print messages that glow in the dark.

Simon, 73, of Churchill, has lost most of his vision over the past decade. He started wearing his message clothes and says it makes a big difference in his ability to get around. "I was a guinea pig and it worked for me. You'd be surprised at how many people offer to help.''

Started just six months ago, his company already has a telephone ordering line and Web site (1-800-357-9906, www.blindwear.com)

Simon was among scores of entrepreneurs displaying products that ranged from the whimsical to the practical to the high tech at last week's American Council of the Blind national convention in Pittsburgh.

And like many, his idea came from experiencing the blind community with a fresh vision.

Paula Wolf of Butler is an aide for a blind girl who was having difficulty grasping math concepts. "Some people can learn better when they can see the problem, if you draw a picture or a diagram.''

So Wolf developed Math Window, which includes a framed magnetic board and symbols in Braille and in print for sighted teachers, so students easily can arrange the numbers and math symbols as sighted students do. $69.75 for the basic kit.(724-285-5428, www.mathwindow.com)

A tricky situation for blind people is standing in line. How can you tell when the person in front of you has moved up?

Enter Guideline's Handguide, a device that detects objects up to 4 feet away. It doesn't replace the cane or guide dog because it can't detect steps or windows, but it enhances a person's ability to get around, said Tony Rogers, president of the Newtown company near Philadelphia.

The hand-held device operated on batteries vibrates when you're near an object. If the person in line ahead of you moves up, it stops vibrating. It also helps people maneuver around furniture or other objects. $159.99 (1-215-860-4455, www.guideline-technologies.com)

One of the most innovative advances that affects whole communities is Talking Signs, an infrared sign system that helps the blind identify buses, trains, automated teller machines and landmarks.

A sign must be equipped with a transmitter that sends infrared signals. The blind or visually impaired person carries a receiver that picks up these signals and decodes it into a voice message that identifies the bus number, building, rest room sign or ATM machine.

The technology has not been installed in Pittsburgh, but it's available in cities in 30 U.S. states, Japan, Finland, Italy and Scotland. San Francisco's board of supervisors passed a resolution to have transmitters installed on signs in all city-owned buildings, and they're in the city's museums, tourist attractions and public transportation systems.

"This is the first time there's been technology to solve a fundamental problem for blind people, and that's travel,'' said Jeff Moyer, company representative who was wearing prototype glasses equipped with the receiver to keep people's hands free.

The sign owner pays $500 for installation of the transmitter; the receiver costs $265. (1-800-339-0117, www.talkingsigns.com).

Pulse Data HumanWare (www.humanware.com) and Freedom Scientific (www.freedomscientific.com) are leaders in assistive technology for people with visual or learning disabilities.

Then there's Bookshare.com, a new online service based in Palo Alto, Calif., that allows people with visual or other disabilities (including dyslexia) to share scanned books, which then can be converted electronically to Braille or to assistive technology.

A project of the nonprofit Benetech Initiative, it acts as a clearinghouse where readers can download from a collection of accessible books. For example, a day after its June 21 release, the book "Harry Potter and the Order of the Phoenix" was available to subscribers. The service costs $25 to subscribe and $50 a year for unlimited book downloads.

Going beyond the practical to the fun, All inPlay, Games with Vision, of Northampton, Mass., offers software games that the blind and sighted can play with each other.

Paul Silva met Tim Keenan, who is blind, when they were students at the University of Massachusetts at Amherst. Silva was looking for a better way to include Keenan in activities he shared with his sighted friends.

So they worked together in developing computer software.

"Our mission is to bring the blind and sighted together on a level playing field,'' said Keenan, who often plays the games poker or crazy eights online with his brother.

"My brother is fully sighted and likes to play because of the cool graphics,'' Keenan said. "But I have just as equal chance of winning as he does.''

More games are being developed. The service connects you to players all over the world and costs $7.95 a month. (1-413-585-9692, www.allinplay.com)

Then, of course, there's Independent Living Aids Inc., which offers an array of talking clocks, watches, thermometers, calculators and tape measures; a coffee cup that sounds a tune when liquid reaches the rim; beeping luggage or key finders; as well as large letter and number phones, reading screens, rulers, playing cards; Braille dice, talking software, etc. (1-800-537-2118, www.independentliving.com).

"This is a very exciting time in history to be blind,'' said Scott McCall, American Foundation for the Blind vice president, in noting all the product and technical advances.

One of the devices that keeps him just as connected to the world as sighted people is HumanWare's Braille-Note. The three-pound, portable gadget about the size of a large book allows him to download material or send e-mail off, write and send e-mail and browse the Internet, with everything converted electronically to Braille.

"I grew up wanting to read the newspaper,'' said McCall of Atlanta. "Until a few years ago, I was dependent on someone else to read the newspaper.

"With this technology, I'm able to get up in the morning and make a cup of coffee, go to my desk, log on to my computer, download my paper and read it as I drink my coffee just like everybody else.''

Virginia Linn can be reached at vlinn@post-gazette.com or 412-263-1662.