Anti-Motion-Artifact Smart Belt With Noncontact Sensing Technique

Electrocardiogram (ECG) is useful for evaluating cardiovascular diseases (CVDs). However, the occurrence of abnormal ECGs in patients with CVDs may be incidental; therefore, long-term ECG monitoring in daily life is important. The conventional Ag/AgCl electrodes with conductive gels are the most frequently used in long-term ECG monitoring; however, they may encounter issues with gel hardening and skin irritation. Several smart wearable devices with dry electrodes have been widely developed in recent years, but they still encounter problems related to skin contact and motion artifacts. In this study, a novel anti-motion artifact smart belt was proposed for long-term ECG monitoring. Based on the technique of capacitive electrodes, the proposed system could access the ECG signal, even across clothing, to avoid the risk of skin irritation and improve the comfort of use. Moreover, a novel motion artifact suppression mechanism was also designed to effectively reduce the influence of motion artifacts. Finally, the electrical specifications and ECG measuring performance of the proposed smart belt were validated, and the efficiency of the anti-motion artifact was also tested. The signal-to-noise ratio (SNR) of the designed electrode circuit was about 44.29 dB, and its bandwidth was set to >0.1 Hz. The power consumption of this system was about 96 mW. For a 1100-mAh Li-ion battery, its operation time was over 33 h. The experimental results indicate that the proposed smart belt could access ECG signals without contacting the skin, and the influence of motion artifacts on the ECG measurement could be effectively reduced.