Unobtrusive wearable health monitoring devices promise to make more widespread and more prompt impact on medical diagnosis and quality of life than implantable devices owing to their ease, comfort, and accessibility of use. For autonomous operation, these sensors are required to harvest energy directly from the environment, the interrogator, or the signal of interest. The technologies and design techniques we have can be directly applied in the wearable setting as well [Ha et al., TBME, 2014]. For example, the wireless power and data telemetry systems that we developed for implantable use [Ha et al., JSSC, 2016] can be immediately adopted into RF-powering wearable sensors. In addition, a non-contact sensing technology with a high front-end gain that we recently developed, and a fully asynchronous vision sensor [Park, Ha et al., BioCAS, 2014] will be essential elements for various sensor applications.
We are attacking three main research directions in this research theme. First, we are investigating flexible-substrate-based sensors for ambulatory health monitoring, entertainment and sport applications while pursuing towards self-powered sensors of a wearable form factor integrated in shoes, gloves or watches.
The second direction is to develop energy harvesting and ultra-low-power circuit components such as analog front-end, ADC, temperature sensor, capacitance sensor, and RF transmitter. These are for extreme applications in the Internet-of-Things paradigm with self-power-havesting from solar, thermal, piezoelectric transducers. Typically, the scavenged power level is very low, less than μW, so conventional electronics are difficult to operate. This requires to utilize two techniques: event-driven computing and ultra-low-power circuit design technique .
The third research direction entails development of smartphone-connected base stations to network with the sensors, utilizing myriad resources related to smartphones, and provide user-friendly interface. This includes development of a smartphone-connected communication module. This mobile base station integrates all the wearable and implantable sensors into a complete integrated system applicable in everyday life and clinical settings.