Conductive Fabric Loop Sensor in Apparel Form for Cardiac Activity Monitoring

Cardiac activity signal sensing performance was analyzed based on the shape of the fabric loop sensor and its position on the body and clothes to study the magnetic field induction conductivity-based detection of cardiac activity signals. The cardiac activity signals of 15 males in their 20 s were measured for each type of fabric loop sensor (spiral loop, extrusion loop, and spiky loop types) and for each measurement position (P2, P4, and P6) by conducting the experiment twice. Statistical analysis quantitatively verified that the highest-quality cardiac activity signals could be obtained when cardiac activity was measured at either P4 or P6 using the spiral loop electrodes. Furthermore, for extrusion loop and spiky loop types of sensors, the cardiac activity signals during ventricular contraction were detected relatively clearly at P4 and P6. As a result, the possibility of applying fabric loop sensors with new shapes was explored. The experimental results show that the extrusion, spiky, and spiral fabric loop sensors could detect cardiac activity signals, although there were some differences in performance. This work should broaden the scope of smart clothing design by considering the aesthetic aspect of clothing design to utilize the fabric loop sensors clothes that measure biosignals.