Design And Research Of Fabric Electrodes For ECG Monitoring

With the change of life style,people pay more and more attention to their health,and the demand for health monitoring equipment is becoming more and more urgent.The electrocardiogram monitoring device,which can detect the physiological indexes of human body and combine with clothing,meets the requirement of health information,and the fabric electrode can satisfy these requirements.The Ag/AgCl electrode,which is used popularly,possesses advantage of low production costs,but remains some problems such as skin allergies and signal reduction after long time use.In addition,the electrode needs to connect the monitor with wires,and it may result in users’ inconvenience and psychological problem.After literature review,it is found that weaving;knitting and embroidering techniques were usually adopted for making fabric electrodes.These electrodes can get ECG signals,but some drawbacks in signal quality,product flexibility,etc.are remained.In addition,a conductive button installed in the center of the fabric electrode may affect contact quality of skin to electrode.In this study,silver-coated knitted conductive fabrics were used as base fabrics,and a layer of nonwoven fabric was laid for preventing fabric unroving.The conductive button was designed to separate with signal collection part in order to avoid the influence of the button to electrode connection.Three size of the collection part was designed in this study;they are circle shape and diameters of 2cm,3cm and 4cm,respectively.These electrodes were treated with chlorination treatments.The impedance spectroscopy of simulated skin with electrode was tested.Experimental results show that impedance values meet the design objectives.The designed fabric electrodes were used to monitor the ecg signal.The electrocardiogram test was carried out using the three-electrode guide method.Clear ECG signals can be detected by using these fabric electrodes.The electrocardiogram of a fabric electrode with a diameter of 4cm is the clearest;its peak voltage of the ecg signal is 0.75958mv.Similar with Ag/AgCl electrodes,three kinds of fabric electrodes can be used for collecting waveforms.The ratio of signal-to-noise detected by the 4cm diameter fabric electrode is 38.67,higher than that obtained by Ag/AgCl electrode.This means that the designed fabric electrode can collect signal effectively.Therefore,the fabric electrode is recommended for further investigation of human electrocardiogram test.