Fig. 3. Fully portable, continuous monitoring of cardiac sounds in daily life.

(A) Series of photos showing different daily activities, including standing-control, talking, walking, and jogging. To demonstrate the device’s performance, the SWS is compared with a rigid device (right photo). (B) Graph showing cardiac sounds measured by both devices during different activities (control, talking, walking, and jogging). The SWS shows motion-artifact controlled data with negligible noise, while the rigid device has corrupted data because of device delamination from motions. (C) Zoomed-in data of measured cardiac sounds; motions from walking and jogging cause noise issues for the rigid one, while the SWS shows negligible effects. (D) Photos comparing two devices (top: SWS and bottom: rigid one) mounted on a soft skin model where the SWS shows conformable contact while the rigid device shows delamination (left photos), and magnified view of device structures without the top encapsulation (right photos). (E) Detailed design of the SWS showing skin-conformal contact for minimizing changes in skin-to-diaphragm air gaps.