IoT-based triboelectric nanogenerator for wrist pulse acquisition and analysis

Wrist pulse plays a critical role in prediction and diagnosis of blood pressure (BP)-related illnesses. Therefore, a low-cost, noninvasive and cuffless BP measurement is highly anticipated. Hence, this study reports a triboelectric nanogenerator to harvest nadi signals for BP measurement. To harvest nadi such as vata, pitta and kapha, the triboelectric nanogenerator is designed and placed on a human wrist; notably, the vata nadi is prone to hypertension. Herein, time domain and frequency domain analyses are performed to identify nadi pulse parameters, which are helpful to monitor the health of subjects. Moreover, an age-wise frequency range of vata, pitta and kapha for male and female individuals are tabulated. The designed triboelectric nanogenerator offers high sensitivity of 0.41 kPa^-1 in the pressure range of 0.01-3 kPa with an ultrafast response time of <3 ms, and no performance degradation is observed after up to 40 000 motion cycles. Thus, the self-powered capability of the triboelectric nanogenerator ensures reliable health care monitoring of parameters such as the heart rate, glucose range, gait and CO₂ levels.