Embracing Self-Powered Wireless Wearables for Smart Healthcare

We present Apollo, a self-powered wireless biochemical system that is wearable and can continuously monitor personal health states. It has three key enablers. First, we design an ultra-low-power Bluetooth backscatter module, which can effectively take BLE signals as excitations and transmit sensor data at high data rates to smartphones. Further, at the core of self-power management is a novel multi-source harvester that can transform RF, light, and thermal energies into electrical energy. Moreover, we introduce a biochemical sensor array that can accurately measure sweat metabolites and electrolytes.We prototype Apollo on a compactly integrated flexible PCB using all commercial off-the-shelf components. Through extensive experiments and field studies, we show that it is able to measure the glucose level in sweat within 5% error rate while consuming 5.8 mW for sensing and 720 pJ/bit for wireless transmissions. This translates to over 1700x lower power than standard electrochemical workstations, and 26x lower power than existing commercial BLE chipsets. We believe Apollo marks an important step towards the dream of ubiquitous healthcare for everyone as it provides a highly convenient, self-managed, and fully integrated way for health monitoring.

I. Introduction

Sweat tells us a lot about human health. Sweat glucose can serve as an attractive candidate for diabetes management; sweat lactate is reported to be a sensitive marker for pressure ischaemia; abnormal concentration of sodium and potassium in sweat could be related to the hyponatremia/hypernatremia and hypokalemia/hyperkalemia; sweat chloride level is currently considered the gold standard for cystic fibrosis diagnosis. So it’s of great importance to continuously monitor human sweat.