An active interface pressure adapter for enhancing sensing capacity and stability of wearable electronics

Wearable hybrid systems offer the potential for continuous and reliable on-skin monitoring of physiological indicators. These systems typically consist of sensing modules, signal processing modules, and protective encapsulation modules, shielding the systems from external environments to enhance their robustness, which in turn compromises interfacial stability. To address this challenge, we introduce a novel interface pressure adapter designed to significantly improve the compliance and stability between the user's skin and the wearable system. This adapter incorporates a micro-airbag, a pressure regulation one-way valve, and a micro-pump, working in synergy to provide sufficient pressure support to the sensing module, thereby enhancing the sensing stability and robustness of wearable systems. As proof of concept, a maximum pressure of 16.2 kPa was generated and regulated with 5 pumping phases to provide back pressure to a pressure sensor for pulse wave measurement. The proposed adapter demonstrated remarkable improvements in interfacial stability and measurement robustness against various joint deformation and motion artifacts. This design presents a promising solution for enhancing the performance and interface stability of contact-based sensing systems.