Estimation of heart rate and respiratory rate by monitoring cardiopulmonary signals with flexible sensor

Monitoring of cardiopulmonary signals plays an important role in many clinical applications. A portable magnetic induction cardiopulmonary signal monitoring system with the flexible sensor of double micro-coils is presented in this paper. The detection of cardiopulmonary signals is realized with double micro-coils. The proposed system is safe, non-invasive, simple, and portable compared with traditional direct contact methods. The Hilbert-Huang transform (HHT) based on complete ensemble empirical mode decomposition with adaptive noise (CEEMDAN) is applied to cardiopulmonary signal processing, decomposing cardiopulmonary signal effectively. The sensor to monitor respiration rate and heart rate is validated and demonstrated with healthy volunteers. The root mean squared errors (RMSE) of heart rate, respiration rate under deep breathing and normal breathing are 3.8 beats/min, 0.61 times/min, and 0.98 times/min respectively. The flexible sensor of double micro-coils has little influence on the measurement results at the bending curvature of 33.9 m