Researchers at Seoul National University's College of Engineering have developed a wearable system that can measure electrocardiograms (ECG) without a battery.
According to the college on Tuesday, a research team led by Professor Yoo Dam of the Department of Electrical and Computer Engineering developed "SkinECG," an ECG measurement system that operates without batteries or wires. The findings were published in the international journal Science Advances on Monday (local time).
Wearable healthcare systems measure biosignals in real time through sensors attached to the body and detect early signs of disease. However, commercialization has been limited by the weight of batteries and the need for periodic replacement.
To address this, efforts have been made to apply "energy harvesting" technology — which converts wasted light or heat into electricity — to wearable devices. The problem was that the locations where sensors are attached differ from those where energy can be efficiently secured. For example, ECG sensors are attached to the chest, but power-generating elements such as solar cells need to be placed on the arms or legs, which receive sufficient sunlight, to achieve high efficiency.
Professor Yoo's team proposed a new structure called an "orthogonal energy harvesting network." Under this approach, power-generating elements attached to the body convert ambient energy into electricity, which is then wirelessly supplied to the ECG sensor through body-coupled powering technology.
Notably, the technology overcomes the limitations of conventional wireless transmission by allowing power to be delivered along the skin surface. This addresses the inefficiency caused by electromagnetic waves being absorbed by the human body when transmitted through the air. In addition, each power-generating element uses mutually orthogonal frequencies, enabling stable power delivery without signal interference.
The team also ensured safety by limiting the power to levels encountered in daily life. Through this, the researchers demonstrated that an ECG sensor can be driven solely by energy harvesting, without batteries or wires. "This technology can be expanded not only as a multimodal digital healthcare platform driving various biosignal sensors such as electromyography and electroencephalography, but also as a foundational power-supply technology for a wide range of wearable devices," Yoo said.
