Cuffless Blood Pressure Estimation Using Magnetic Flux In A Ring Form Factor

Smart rings represent a promising frontier in wearables for pervasive physiological health monitoring. They offer convenient and unobtrusive wear and reliable and firm contact with the finger for higher sensing fidelity. However, their use for monitoring complex physiological parameters with clinical use-cases, such as blood pressure (BP), still remains a challenge. While existing approaches including optical (e.g., PPG) and electrical (e.g., bio-impedance) modalities offer great promise, the direction to measure small mechanical movements of the skin due to blood volumetric changes and convert this to BP provides an exciting and complementary direction. Our Hall effect ring sensor can capture variations in magnetic flux due to the underlying pulsatile activity at digital arteries. We provide an end-to-end analysis to assess the performance of our smart rings in estimating BP. Our results indicate that we achieved a mean absolute error (MAE) of 4.79 mmHg and 2.61 mmHg for systolic and diastolic blood pressure, respectively, demonstrating the potential of this innovative design for clinical applications.