Design of Automatic Adjustment Noncontact Sensing Smart Clothing

Electrocardiogram (ECG), usually measured by Ag/AgCl electrode with conductive gels, is one of the most frequently used tools for the diagnosis of cardiovascular diseases (CVDs) symptoms, but it may encounter the gels drying issue and the risk of skin allergic reaction for long-term ECG monitoring. Recently, the technique of noncontact electrode has developed to access biopotentials without contacting the skin directly to improve the above issue and the convenience and comfort of use, but its signal quality may be affected by the fabric material and the skin-electrode interface condition that still cannot be monitored by current wearable devices. In this study, a novel automatic adjustment noncontact sensing smart clothing was proposed. The designed smart clothing could access biopotentials without contacting the skin directly. Moreover, the function of real-time skin-electrode interface capacitance monitoring was also built to monitor the interface condition simultaneously. The attenuation compensation mechanism was also designed to automatically compensate the attenuation of ECG signal according to the fabric material and the change of interface condition. Finally, the system performance was validated, and the influence of fabric conditions and motion artifact on the change of interface capacitance and ECG signal quality was also investigated. From the experimental results, its ECG signal quality was similar to that of the conventional Ag/AgCl electrodes (correlation >95%) and was stable for long-term monitoring, and the cotton fabric material, thinner fabric thickness, and sweating condition would also improve the ECG signal quality.