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In the awful event that you are trapped inside a collapsed building, the options you have for letting rescuers know that you're still alive are limited.

Hopefully rescue dogs will pick up your scent, or a keen-eared rescuer will hear your shouts through the rubble.


But now it could be your very heartbeat that saves your life.

Nasa's Jet Propulsion Laboratory and the US Department of Homeland Security's Science and Technology Directorate (S&T) have developed and tested a device that detects the heartbeats of people buried under collapsed buildings.

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The device -- straightforwardly named "Finding Individuals for Disaster and Emergency Response" or Finder -- uses microwave radiation to detect the chest movements associated with heartbeats and breathing.

In tests carried out in June of this year, Finder was able to detect the presence of a heartbeat through nine metres of crushed material and six metres of solid concrete. In open spaces it was able to detect a heartbeat at a distance of 30 metres. "Testing proved successful in locating a VA-TF1 [a search and rescue team] member buried in 30 feet (nine metres) of mixed concrete, rebar, and gravel rubble from a distance of over 30 feet," said John Price, a S&T programme manager.


Finder builds on work carried out at Michigan State University in the 90s, in which a team of researchers showed that it was possible to use microwave radiation to detect movements in the chest caused by heartbeats. "When the human subject is illuminated by a microwave beam, the reflected wave from the human subject will be [altered] by the subject's body movements, which include the breathing and the heartbeat," notes a paper detailing the research, published in

IEEE Transactions on Bio-medical Engineering in 2000.

If the signal can be properly processed, it adds, "the breathing and heartbeat signals of the subject can be extracted".

The research also inspired other approaches to detecting heartbeats, including a vibration-detecting sensor first developed as a means of finding potential intruders hidden in vehicles at the US Department of Energy's Oak Ridge Y-12 installation, where nuclear weapons components are produced.

Later the vibration technology would be sold by a company called


GeoVox, whose customers include UK Border Control.

At the moment, the microwave radiation approach developed for finding people trapped under rubble is yet to be commercialised, but it is hoped that it will be ready for market by Spring 2014. It is currently able to detect the presence of a heartbeat, but with further development should also be able to determine the exact location of the person.

Image: rijans/Flickr/CC