Wireless EEG system self-powered by body heat and light

Apr 09, 2008
Wireless EEG system self-powered by body heat and light
The wearable wireless EEG system with hybrid power supply.

In the framework of Holst Centre, IMEC has developed a battery-free wireless 2-channel EEG (electroencephalography or monitoring of brain waves) system powered by a hybrid power supply using body heat and ambient light. The hybrid power supply combines a thermoelectric generator that uses the heat dissipated from a person’s temples and silicon photovoltaic cells. The entire system is wearable and integrated into a device resembling headphones. The system can provide more than 1mW on average indoor, which is more than enough for the targeted application.

Thermoelectric generators using body heat typically show a drop in generated power when the ambient temperature is in range of the body temperature. Especially outside, the photovoltaic cells in the hybrid system counter this energy drop and ensure a continuous power generation. Moreover, they serve as part of the radiators for the thermoelectric generator, which are required to obtain high efficiency.

Compared to a previous EEG demonstrator developed within Holst Centre, which was solely powered by thermoelectric generators positioned on the forehead, the hybrid system has a reduced size and weight. Combined with full autonomous operation, no maintenance and an acceptable low heat flow from the head, it further increases the patient’s autonomy and quality of life. Potential applications are detection of imbalance between the two halves of the brain, detection of certain kinds of brain trauma and monitoring of brain activity.

The system is a tangible demonstrator of Holst Centre’s Human++ program researching healthcare, lifestyle and sport applications of body area networks. Future research targets further reduction of the power consumption of the different system components of the body area network as well as a significant reduction of the production cost by using micromachining. Interested parties can get more insight in this research or license the underlying technologies through membership of the program.

The thermoelectric generator is composed of six thermoelectric units made up from miniature commercial thermopiles. Each of the two radiators, on left and right sides of the head, has an external area of 4×8cm² that is made of high-efficiency Si photovoltaic cells. Further, thermally conductive comb-type structures (so-called thermal shunts) have been used to eliminate the thermal barrier between the skin and the thermopiles that is caused by the person’s hair on the thermoelectric generator.

The EEG system uses IMEC’s proprietary ultra-low-power biopotential readout application-specific integrated circuit (ASIC) to extract high-quality EEG signals with micro-power consumption. A low-power digital-signal processing block encodes the extracted EEG data, which are sent to a PC via a 2.4GHz wireless radio link. The whole system consumes only 0.8mW, well below the power produced to provide full autonomy.

Source: IMEC

Explore further: Researcher launches successful tech start-up to help the blind

add to favorites email to friend print save as pdf

Related Stories

Power arm band for wearables harvests body heat

Apr 12, 2014

(Phys.org) —A group of Korean researchers have turned their focus on supplying a reliable, efficient power source for wearables. Professor Byung Jin Cho of the Korea Advanced Institute of Science and Technology ...

Student's flashlight works by body heat, not batteries

Jul 01, 2013

(Phys.org) —Ann Makosinski from Victoria, British Columbia, has an LED flashlight powered by body heat. This inventor has a flashlight that glows when she holds it. The story gets more interesting, though. ...

Fujifilm breaks record with thermoelectric material

Feb 07, 2013

(Phys.org)—Photographic film maker Fujifilm has been busy this year at the Nanotech 2013 conference being held in Tokyo. First came news of bendable/roll up speakers. Now the company is showing off a new thermoelectric ...

MEMS device generates power from body heat

Apr 29, 2010

(PhysOrg.com) -- In an attempt to develop a power source that is compact, environmentally friendly, and has an unlimited lifetime, a team of researchers from Singapore has fabricated an energy harvesting device ...

Recommended for you

Large streams of data warn cars, banks and oil drillers

Apr 16, 2014

Better warning systems that alert motorists to a collision, make banks aware of the risk of losses on bad customers, and tell oil companies about potential problems with new drilling. This is the aim of AMIDST, the EU project ...

User comments : 0

More news stories

Hackathon team's GoogolPlex gives Siri extra powers

(Phys.org) —Four freshmen at the University of Pennsylvania have taken Apple's personal assistant Siri to behave as a graduate-level executive assistant which, when asked, is capable of adjusting the temperature ...

Better thermal-imaging lens from waste sulfur

Sulfur left over from refining fossil fuels can be transformed into cheap, lightweight, plastic lenses for infrared devices, including night-vision goggles, a University of Arizona-led international team ...

Deadly human pathogen Cryptococcus fully sequenced

Within each strand of DNA lies the blueprint for building an organism, along with the keys to its evolution and survival. These genetic instructions can give valuable insight into why pathogens like Cryptococcus ne ...