A feasibility study on a low-cost, smartphone-based solution of pulse transit time measurement using cardio-mechanical signals

This paper presents a pilot study on a new method of measuring pulse transit time (PTT) using a commercial smartphone. An application based on an Android smartphone is developed to collect seismocardiogram (SCG) and gyrocardiogram (GCG) signals. The system is designed with a minimized amount of external sensors to reduce the total cost and complexity of the system. PTT measurements are calculated as a time difference between the fiducial points in photoplethysmography (PPG) recordings from a reference sensor module and SCG or GCG signals detected by the internal inertial sensors of a smartphone. A DSP system is designed and experimentally tested on five healthy subjects at rest. Our results suggest that the proposed solution could be a promising method to develop a low-cost, home-based PTT monitor.