Presentation Information
[11p-C214-2]Eyeglass-based monitoring of respiration and cardiovascular trends with ultrahigh-sensitivity strain sensors
〇(P)Dohoon Lee1, Naruhito Seimiya1, Kuniharu Takei1 (1.Hokkaido Univ.)
Keywords:
eyeglass wearables,crack-based strain sensors,laser-induced graphene
Continuous and unobtrusive cardiopulmonary monitoring remains challenging because conventional measurements require bulky instruments or skin-mounted devices, which can limit comfort and long-term wearability. Here, we present an eyeglass-based system for non-adhesive monitoring of respiration and cardiovascular trends during daily activities. Ultrahigh-sensitivity strain sensors were integrated into the eyeglass nose pads and frame hinge detect nasal and oral breathing. The nasal sensor employs a crack-engineered carbon/laser-induced graphene (LIG) bilayer structure on a polyimide substrate. A stripe-like polyimide-derived LIG network provides mechanical interlocking and stable electrical conduction under deformation. The sensor exhibits a gauge factor of approximately 14,567 at 1.5% strain and stable performance over more than 2,000 loading cycles, enabling detection of small respiration-induced nasal deformations. The system enabled real-time nasal-breathing detection and complementary oral-breathing detection across different activity conditions. Respiration depth and breath-to-breath interval extracted from the nasal sensor signals were used in a simple multiple linear regression model to estimate time-series trends in R-R interval (RRI), systolic blood pressure (SBP), and diastolic blood pressure (DBP). Across four participants (N = 4), correlations with reference measurements were r = 0.73, 0.67, and 0.58 for RRI, SBP, and DBP, respectively. Experiments during desk work, rest, exercise, and post-exercise recovery demonstrated simultaneous monitoring of respiratory activity and cardiovascular trends.