Engineering a pulse rate monitoring glove

摘要

Pulse rate (PR) is an important physiological parameter and can offer an indication of physical exertion. As such, optical pulse rate monitors for fitness tracking have grown in popularity in recent years and have featured as a component of many activity trackers and smart watches. These devices typically measure pulse rate using photoplethysmography (PPG) which requires an arrangement of a light emitting diode (LED) and a photodiode. The LED will emit light onto the skin and a portion of the light spectrum will be absorbed depending on the blood volume, with the transmitted or reflected light being measured by the photodiode. By recording the changes in the blood volume PR can be determined. This work presents a PR monitoring glove where an IR LED and a photodiode necessary for PPG have been discretely integrated into the structure of a textile. This has been achieved by using electronic yarn (E-yarn) technology where small electronic chips are soldered onto fine wires, encapsulated within a resin cylinder, and covered in fibers to create a mechanically and chemically robust yarn that looks and feels like a normal textile. The yarn production process, and the integration of the yarns into a textile, will affect the light emitted/collected by the optical components and these affects need to be fully quantified and understood so that an optimal sensing device can be engineered. Building on earlier studies this work investigates important design consideration, such as the emission pattern of the LED embedded E-yarns, in order to create a PR monitoring glove.