STATE COLLEGE, Pa. -- Call it the Spiderman alert system.

Using acoustics technology, researchers at Penn State University have found a way to turn a simple chain-link fence into a breach detector.

"The idea was to make kind of like a spider web, where you have a wire that can very easily pick up vibrations," said David Swanson, a senior researcher at Penn State's Applied Research Laboratory.

In addition to companies interested in licensing it for development, the Penn State "smart fence" has drawn the attention of the U.S. Army and Navy, the Federal Aviation Administration, water utilities and oil companies, university officials say.

The invention relies on a single strand of galvanized steel wire woven into the fence or strung just inside it, a system of springs and weights and inexpensive ground sensors.

Because a chain-link fence rattles at the slightest touch, the wire relays those vibrations. Geophones -- rugged, off-the-shelf sensors placed on the ground -- are used to transmit the vibrations to a personal computer.

A simple concept, it took just a year to develop, and Swanson said it could be adapted for other types of fences.

At minimum, the sensors can be programmed to transmit sound through speakers to alert security. A demonstration model set up around an ARL research facility made an earsplitting racket when a small stone struck the fence.

A more sophisticated application would have the computer analyze the volume and noise frequency to determine the size of the intruder, then track the time it takes for sound to travel to pinpoint where the fence was being breached.

Customized systems

From there, the possibilities are nearly endless.

The computer could determine that the noise is just the wind or a small animal and disregard the signal.

If it interprets a threat, the computer could alert security, train video cameras on the location, even launch countermeasures. Lights could be activated, tear gas released.

"Everything about this system can be customized to the needs of the client, both for security and for deterrence," said Nick Nicholas, a consultant at the lab. "In an airport or a power plant, where one security guard may be watching 40 video screens, the computer might tell the guard to look at a certain screen and train video cameras on the intruder. Or in your backyard, if someone is trying to climb the fence and swim in your pool, it could turn on the porch light or have a speaker say, 'Get out of here.'"

The system is not designed to replace human security, Swanson said. Instead, it amplifies the sensory capability of the security already in place.

"This is the first line of defense in a larger security system," said Dave Rigsby, a research associate at the lab.

Needs a boost

And perimeter security could use a boost.

Paul Dempsy, who directs the transportation law program at the University of Denver, says perimeter security at most airports "is simply a chain-link fence, and occasionally a security officer will ride the perimeter to see if there are breaches in the fence."

Penn State University owns the patent rights, but is barred from marketing the technology itself because it's a land grant school.

Rick Weyer, the university's technology licensing officer, said three U.S. companies have expressed an interest in developing and marketing the "smart fence," as have corporations in Germany, Switzerland and Hungary. He would not name any of them.

Among concerns that have also expressed interest in the technology, said Swanson, are "municipalities for protecting water supplies, oil companies for protecting pipelines and refineries and tank farms, a large foreign company concerned about nuclear power plants."