Portable Chest-Worn Device for Simultaneous Detection of Phonocardiogram and Seismocardiogram Using Piezoelectric Films Sensors

The simultaneous detection of different heart signals provides information about cardiovascular health but typically involves attaching multiple sensors to the body, which can lead to discomfort during long-term measurements. In this work, we propose a different approach to simultaneously detect the phonocardiogram (PCG) and seismocardiogram (SCG). It relies on using two piezoelectric films implemented in a single portable chest-worn device, reducing the number of devices attached to the body. Besides, since these sensors do not require any power supply, the power consumption is considerably reduced. This innovative approach offers a potentially more comfortable alternative for long-term applications, reducing user discomfort. Because both signals have different frequency components, both sensors were strategically coupled to a stethoscope membrane using a custom-built case. The device was tested on a healthy volunteer. It was able to simultaneously detect the PCG with an SNR higher than 34 dB and the SCG with an SNR higher than 62 dB. The electronic circuitry was battery-supplied, and its current consumption was lower than 65 uA. The possibility of establishing a client/server connection via sockets was also demonstrated, which allows sending of data to the cloud/fog where intelligence algorithms could be implemented.