WaveFlex Sensor: Advancing Wearable Cardiorespiratory Monitoring With Flexible Wave-Shaped Polymer Optical Fiber

In this work, we propose a wearable cardiorespiratory monitoring sensor, the WaveFlex sensor, which incorporates a flexible wave-shaped polymer optical fiber. The stretchable polydimethylsiloxane (PDMS) material maintains the wave-shaped structure of the polymethyl methacrylate (PMMA) optical fiber, connected to the inelastic fabric on each side to form the sensor. The WaveFlex sensor enables accurate cardiorespiratory monitoring, tested on ten subjects in standing, sitting, and lying positions. Signal processing techniques such as power spectrum analysis and finite impulse response (FIR) theory extract respiration rate (RR), heart rate (HR), respiratory, and heartbeat waveforms. The sensor exhibits high accuracy, with errors of less than 9% for RR and less than 3% for HR. The proposed WaveFlex sensor also allows for the timely monitoring of apnea through frequency and time domain analysis, offering a simple and cost-effective optical solution for wearable health applications.