Research Of The Non-Contact ECG Measurement System

Cardiopathy is one of the most prevalent diseases in endangering people's health. And ECG is an important diagnostic tool for assessing heart function. For the purpose of long-term, everyday electrocardiogram (ECG) monitoring, A simple, safe, and efficient non-contact ECG measurement system using e-textile is described in this paper. This system does not require any direct conductive contact between the electrodes and the skin of human, it can detect subject's ECG accurately. The system is composed of the non-contact electrodes, an ECG data acquisition unit, an ECG signal processing unit and a PC-based analysis platform.In the hardware design, two e-textile electrodes and an indirect-skin-contact ground sheet are fixed in the bed. ECG signal is captured by non-contact e-textile electrodes, and then sent to the data acquisition unit, which including voltage followers, an instrumentation amplifier, a 4^th order high pass filter, a 4^th order low pass filter, a 50Hz double T notch filter with adjustable Q value, a common mode rejection circuit amplifier with adjustable gain and a level shift circuit; The obtained ECG signal is processed and transmitted by an ECG signal processing unit based on a 16-bit high-integrated, ultra low-power MCUMSP430, reducing the circuit and decreasing the consumption.In the software design, the firmware for MSP430 is programmed by C language,which can be used for ECG signal collection, storage and transmission toPersonal Computer (PC) at real time. The PC-based analysis platform wascreated using graphic language LabVIEW, which can be used for ECG signalstorage, analysis and display.The results show that the system is safe and easy to operate. This concept ispotentially useful in self ECG monitoring for home healthcare. However, thesignal quality is poorer than that obtained using conventional method, but "R"peaks of ECG signals are large enough to be auto-detected. In the future we willimprove these problems of this system.