Engineers at Pennsylvania State University have invented a wireless microphone that could improve the success of rescue missions in locating survivors trapped under collapsed buildings. The research was inspired by futile attempts to help locate victims buried in the World Trade Center rubble.

Tom Gabrielson, a senior research associate at Penn State’s Applied Research Laboratory, spearheaded the project soon after Sept. 11, 2001. He brainstormed ideas with Urban Search and Rescue (USAR) workers at Ground Zero to develop a device that could be put into compact, dangerous areas without hauling around cables. The device also provides a way for rescuers to probe areas that are too risky to enter.

Gabrielson called Matthew Poese, research associate at the Penn State Applied Research Labs and graduate student in acoustics, to help design this device. Poese said their motivation for the microphone was to help USAR teams accomplish their goals while staying safe and ultimately saving the lives of trapped victims.

“The idea is that a USAR guy on a rubble pile or other type of disaster site could just throw these balls — baseballs, really — into the pile or other dangerous area that have a wireless microphone in them and then monitor the response at a safe location,” Poese said.

The microphones, or “sensors,” will help improve rescue missions. They will not, however, replace current techniques for locating survivors. There are two main methods for finding victims. One is to yell and ask for a response. Another is vibration and noise sensors that are lowered into voids in collapsed wreckage. Rescuers then shout or use bullhorns and listen for a response on the sensors.

Both of these systems have a central unit for listening, which means that rescuers have to get close to the wreckage, putting themselves at risk. The wireless microphones help avoid this problem. Penn State researchers claim search-and-rescue teams will have a better chance of finding survivors if these microphones are deployed.

William Sethares, associate professor in electrical and computer engineering at the University of Wisconsin, said the microphone’s function seems “very reasonable since there are few sources of noise underground.” He also said the design is more a repackaging of a common idea than a breakthrough in technology.

Sean Garster, a UW junior, agrees.

“It sounds like a good project but not anything incredibly unique,” Garster said. “I’m sure it would help other technology … It is important.”

The research on this technology has mainly been a volunteer effort confined to Penn State laboratories. Other than some minor technological glitches, the device works fairly well, Poese said. It does not need to be indestructible because it is very cheap. This allows it to be widely manufactured and used for a variety of tasks.

Poese said the researchers aim to make the microphone available to USAR teams and law-enforcement agencies in the near future.