After a car accident left him blind three years ago, Ted Henter knew his career as a motorcycle racer was over.

The 30-year-old Forest Hill man took up computer programming, but it was a cumbersome business. For every word he typed into the computer he had to wait for a Braille printout to make sure he had it right.

Then he discovered the genius of Deane Blazie, a modern-day miracle worker from Forest Hill who has invented a talking computer terminal that reads back everything written on the screen.

"It's a tremendous advantage," said Henter, who now works for Blazie's company, Maryland Computer Services Inc., which sells its Total Talk machine for $6,000.

With the new computer, which speaks in a robot-like voice, "I have almost as good a chance to get a job as a sighted person," Henter said. "It's so fast, it's like reading the information yourself."

Blazie's invention, unveiled last year and now sold around the world, is one of more than 900 computer-based devices entered in the Johns Hopkins Applied Physics Laboratory's first competition to select the best such inventions for use by the handicapped.

This weekend, Blazie and 29 other finalists will exhibit their creations at the National Academy of Sciences in Washington. A grand prize winner, to receive $10,000, will be announced Monday.

Paul L. Hazan, director of the project for the Laurel laboratory, said the inventors used "an amazing range" of ideas in designing equipment for the blind, deaf, mentally retarded, learning-disabled, orthopedically handicapped and persons with neurological and muscular problems.

The contest, launched last November, was "pretty ambitious," Hazan concedes. "We wanted to focus the power of this new low-cost computer technology on the needs of the handicapped. And we wanted to harness creativity on a national scale, not just from professionals in the field, but from the general public too."

Like Blazie, whose innovation was inspired by a blind friend, most of the inventors had in mind someone special who could use the computer to solve a practical problem, Hazan said.

For instance, Howard Batie, a Navy officer from Herndon, Va., developed a system that enables a 50-year-old woman with cerebral palsy to communicate for the first time in her life.

Batie, who dabbles in computers as a hobby, designed a gadget that lets the woman, who has been spastic and speechless since birth, display words and phrases on a screen by pressing five large buttons connected to a basic Radio Shack computer.

Another custom-made invention was dreamed up by Reuel Launey, an Arlington physicist. He designed a voice-controlled computer a quadriplegic can use to operate home appliances, a telephone, a typewriter and other office equipment.

Launey's machine, which says "Good morning, Human," turns on the lights and tells him the time when he wakes up, was made for David Ward, a suburban Baltimore man who is paralyzed from the shoulders down.

Ward, who sold industrial equipment before he lost the use of his arms and legs in a fall four years ago, was unable to turn pages in catalogs and price lists. Launey said he plans to connect his computer to a microfiche version of the catalogs, so Ward can orally call up the information he needs to conduct his business.

Other examples of computer wizardry on display this weekend:

* An infrared-eye tracking system that allows a nonvocal, severely handicapped child to express words or phrases audibly, simply by glancing at them on a personal terminal screen. An infrared camera associates the position of the child's eyes with a specific word; then the computer says the word in a little girl's voice.

* A computer that teaches deaf children to lip-read by outlining lips, mouth and tongue on a screen and moving them to pronounce words.

* A computer the size of a pocket calculator that a deaf person can use in a phone booth to relay a message to his personal computer at home.

After the contest, Hazan said, Johns Hopkins will sponsor a workshop so the inventors can meet potential manufacturers of their devices and educators who could use them.

"The bottom line," he said, "is getting these programs in the hands of the handicapped."

You can see these inventions from noon until 4 p.m. Saturday and Sunday in the Great Hall of the National Academy of Sciences, at 21st Street and Constitution Avenue in Washington. Admission is free.