iLancet™ Autonomous Smart Bracelet

Reflective photoplethysmography (PPG) has become the default sensing technique in wearable devices to monitor cardiac activity via a person’s heart rate (HR). iLancet™ Autonomous Smart Bracelet is a self-powered wrist-worn platform for continuous, unobtrusive physiological sensing; it is being designed to measure PPG signal from the radial artery on the anterior (ventral) side of the wrist: its sensor array module shall consist of a multiwavelength array of an infra-red (IR) light, a red light and a green light emitting diode LED, a photodetector (PD), and a 3-axis accelerometer. The accelerometry signal will be used to remove motion interference from PPG signals, while the infrared wavelength range is a motion reference for adaptive filtering. The design is autonomous i.e., self-sustaining, ultra-low power combined with solar energy harvesting and real-time IoT analytics. Today, a majority of commercial wrist-worn devices sense PPG signals and estimate heart rate (HR) from the usual central zone of the posterior (dorsal) surface of the wrist, which is limited to monitoring cardiac activity or heart operation through the micro-vascular bed of capillaries and tissue of the posterior wrist.