Development and Optimisation of Textile-Based Optical Sensors for Cardiac Health Monitoring

Wearable cardiac health monitoring could play a crucial role in managing an individual's cardiac health conditions. This study focuses on the development and optimisation of a textile-based optical sensor system utilising photoplethysmography (PPG) technology for continuous cardiac health monitoring. Light Emitting Diode (LED) and Photodiode (PD) electronic yarns were engineered by embedding these components into textile yarns. This is achieved by first soldering the component onto Litz wires, then by encapsulating the component inside a protective resin pod, and finally by covering the component in a braided structure. The optical properties of the E-yarns were optimised by exploring various resin micro-pod configurations and braiding techniques. The optical behaviours (transmission and reflectance as a function of wavelength) of the resin pods have been characterised. A prototype, knitted textile glove capable of monitoring blood volume variations and generating PPG waveforms has been realised. This system was validated by recording pulse rate (PR) readings from ten human subjects confirming its functionality and accuracy as a textile-based optical sensing system. This work demonstrates significant progress in integrating advanced optical sensors into wearable textile platforms, promising enhanced functionality for cardiac health monitoring applications.