Wearable Fabric Loop Sensor Based on Magnetic-Field-Induced Conductivity for Simultaneous Detection of Cardiac Activity and Respiration Signals

• Published in: Sensors (Basel, Switzerland) Vol. 22; no. 24; p. 9884
• Main Authors: Cho, Hyun-Seung, Yang, Jin-Hee, Lee, Sang-Yeob, Lee, Jeong-Whan, Lee, Joo-Hyeon
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 01.12.2022; MDPI
• Subjects: Analysis; apparel form-wearable platform; Biometrics; cardiac activity signal; clothing structure; Electric Conductivity; Electrocardiogram; Electrocardiography; Electrodes; fabric loop sensor; Heart; Humans; Magnetic fields; Male; Methods; Personal health; Respiration; respiration signal; sensor configuration; Sensors; Textiles; Wearable computers; Wearable Electronic Devices; Yarn; South Korea; clothing structure; apparel form-wearable platform; sensor configuration; cardiac activity signal; fabric loop sensor; respiration signal
• ISSN: 1424-8220; 1424-8220
• DOI: 10.3390/s22249884

In this study, a noncontact fabric loop sensor based on magnetic-field-induced conductivity, which can simultaneously detect cardiac activity and respiration signals, was developed and the effects of the sensor’s shape and measurement position on the sensing performance were analyzed. Fifteen male subjects in their twenties wore sleeveless shirts equipped with various types of fabric loop sensors (spiky, extrusion, and spiral), and the cardiac activity and respiratory signals were measured twice at positions P2, P4, and P6. The measurements were verified by comparing them against the reference electrocardiogram (ECG) and respiratory signals measured using BIOPAC® (MP150, ECG100B, RSP100C). The waveforms of the raw signal measured by the fabric loop sensor were filtered with a bandpass filter (1–20 Hz) and qualitatively compared with the ECG signal obtained from the Ag/AgCI electrode. Notwithstanding a slight difference in performance, the three fabric sensors could simultaneously detect cardiac activity and respiration signals at all measurement positions. In addition, it was verified through statistical analysis that the highest-quality signal was obtained at the measurement position of P4 or P6 using the spiral loop sensor.