Sweat-Powered, mm-Scale, Continuous-Time Sensor Systems With Bluetooth Low Energy (BLE) Backscatter

Personal healthcare monitoring is a promising field, as continuous, individual-specific, real-time health information can enable better care and more precise diagnoses. One barrier to continuous monitoring lies in the power requirements and data retrieval needed for on-body sensors, as well as the need for measurements in different locations on the body. Ideally, these sensors would be self-powered, unobtrusive, and compatible with low-power communication systems. However, existing wireless self-powered on-body sensors are often limited by energy constraints, making real-time data transfer challenging with conventional Bluetooth communications. In this work, we present a wearable, self-powered on-body sensor system that utilizes an ultra-low-power backscatter radio scheme to enable real-time wireless communication, powered by sweat batteries, thus eliminating the need for external power. We demonstrate the capabilities of this system with a continuous, real-time electrocardiogram (ECG) system that transmits data to a cell phone held by the user.