London, Apr 19 : A car that can respond to stressed users, new ways to interact with computer games, and techniques that can enable doctors to monitor patients at risk of seizures - all this would soon be possible, thanks to a lightweight battery-free headset that can constantly monitor human brainwaves.
Researchers at the Interuniversity Microelectronics Centre (IMEC), in Belgium have created this portable electroencephalogram (EEG) device, resembling a headset, which works by continuously monitoring human brainwaves, and runs by body heat and sunlight.
The device makes use of thermoelectric materials which turn heat gradients into electrical energy and generates power by using the difference between a warm human head and the cooler surrounding air
Earlier a similar prototype of the same was also created based on the above phenomenon, but it was sometimes short of power.
"If there is a lot of sun, it is quite hot, the temperature difference between the body and the environment is small," New Scientist quoted Guy Beaucarne of IMEC, as saying.
This implied that the problem lies in thermoelectric materials, which cannot produce much power, but the solution was found by installing two solar panels to the device. The solar panels also have heat sinks that cool the device to preserve the thermal gradient needed by the thermoelectrics.
"Typically in such conditions you have more sunlight, so the solar generator compensates for the low thermoelectric power," said Beaucarne.
Having comb-like structures to collect body heat through hair, this headphone-like device is more comfortable than the original, which covered the skin of the forehead to harvest heat.
Mostly, this new device is capable of producing at least 1 milliWatt of power, more than the 0.8mW required for detecting electrical activity observed in the brain, and transmitting it over wifi to a computer.
While comparing the new headset to the previous device, Chris van Hoof, also of IMEC said: "Using both power sources, you get twice as much power, so it's roughly half the size."
He said that this portable headset should show how the brain functions in environments it has not been studied in before and small, preclinical trials have already shown that the headset collects data identical to those of EEGs used in hospitals.
In fact, Van Hoof said that its low weight and mobility would certainly make it ideal for providing biofeedback on soldiers. Not only this, cars that can track the brainwaves of drivers can reduce people's mental workload at times of stress by responding to brain states. As it is a portable headset, this would be easily possible on the battlefield or in other areas. It could also be used to monitor patients at risk of seizure or as an interface for computer games.
One of its immediate application can be that it can facilitate the studying of sleep in people's own homes, instead of in hospital wards where sleep patterns can be disturbed.
"The more portable and unobtrusive the system, the more true to life the data will be," he said.
Perfecting such small autonomous power sources could open up a host of new applications, said Arthur DiMartino, of medical technology company TechEn in Milford, US.