Ultrasound sensors and its application in human heart rate monitoring

Noninvasive wearable human health monitoring devices are developed to improve the comfort, convenience, and security of humans in their life. Ultrasound technology has been used for imaging the human body for over half a century. In this study, the use of ultrasound as a wearable device for human health monitoring is introduced. This work investigates analysis of the heart motions for heart rate extraction. Experimental results showed promising performance of the proposed method in reference to an electrocardiogram device. A low power and low complexity hardware prototype is designed to measure the Time Of Flight (TOF) and amplitude of reflected ultrasound signals generated by piezo sensors at 1 MHz (nominally), under design considerations for safety issues of intensity exposure defined by FDA. This type of a wearable human-interactive device represents a promising platform not only for heart rate measurement but also for more feasible features such as respiration rate. A new technique is applied to minimize the signal processing time and ensure the device response correctness.