Patrick J. Cudmore lives by himself on Durbury Beach, with no connection to phone or power lines. He generates his own electricity, takes long walks by the ocean and invents in solitude.

"I'm the prototypical lone inventor," he says. "I have a studio in my home, and I test all my devices in great secrecy."

For 15 years, the visiting lecturer in the Visual and Environmental Studies department has been a practicing inventor, devising creations ranging from flying automobiles to egg-shaped rocking capsules.

Garbed in a business suit and carrying a briefcase, Cudmore arrives at Harvard twice a week looking like a traditional academic.

But the contents of his briefcase yield a clue to the South Dakota native's unconventional nature. From it he pulls fold-up children's kites, plastic toys to throw or spin, glossy photographs of speeding boats, sketches of cars with propellers cruising through the air and numerous patents, complete with golden seals.

Cudmore estimates that he has roughly 200 ideas for devices in his files, although none of them are currently in production. Twelve of his inventions have been patented, and two toy designs were produced by a major toy company.

The Carpenter Center featured a collection of the inventor's works last fall. And in 1982, the Boston Museum of Science displayed a full exhibit of his inventions, which include car mirrors that eliminate blind spots, roller skates that can be used on rough surfaces and flying windmills.

An invention that he is particularly enthusiastic about is a hydro-foil sailboat designed to sail at twice the speed of the wind propelling it. The boat was a finalist in the 1981 international Rolex Awards for enterprise.

The 45-year-old says that sometimes his ideas are met with incredulity. For instance, people often are initially skeptical of his "Skyro" invention, which is a plastic, cylindrical-shaped toy that "flies horizontally, like a laser, for hundreds of feet, and doubles as a bracelet."

"But once they see it work," says Cudmore, "they become believers for life." Both "Skyro" and "Bug-Eye," a hand-held portable microscope that enables children to view living insects, have been marketed by Milton Bradley.

The principle behind "Skyro," a wing that moves forward like an airplane propeller and has the verticle lift of a helicopter, is one that will enable automobiles to fly someday, says Cudmore.

"I tried out my idea for a flying car on General Motors and was told 'We don't have a policy on flying automoiles and therefore aren't interested,"' he says.

"The problem with being an independent inventor," says Cudmore, "is that once you make something, you never know how well it will do. It's completely out of your hands." Patents are expensive, ranging in price from $3000 to $20,000.

Researching and creating a prototype of an invention is also costly, requiring a variety of individual and corporate sponsors. Nearly $100,000 was invested on the last model of the hydrofoil sailboat, for example.

Cudmore says he dislikes the business side of marketing his inventions, preferring instead the "excitement of discovery."