A smart face mask based on photoplethysmography for cardiorespiratory monitoring in occupational settings

In recent years, the market dedicated to wearable devices has undergone a strong expansion due to the increasingly development of innovative and personalized technologies for monitoring vital parameters. The COVID-19 pandemic has led the change in daily habits through the introduction of personal protective equipment (e.g., face mask) into everyday routine. The use of an instrumented face mask to monitor heart rate (HR) and respiratory rate (RR) of workers in occupational settings may be useful to better understand the physiological conditions and the presence of environmental and physical stressors.Among many methods used to estimate these two vital signs, photoplethysmography has gained broad acceptance in the scientific community. Several sites have been used to place the photoplethysmographic sensor (e.g., ear lobe and finger-tip) to estimate the above-mentioned physiological parameters. In this paper, we proposed a smart face mask (SFM) instrumented by a photoplethysmographic sensor. This configuration is particularly adequate to be used in those occupational settings which require the use of common input peripherals (e.g., mouse and keyboard) which prompt to fast movement of hands and fingers, limiting the performance of common measurement systems (e.g., smartwatches) due to motion artifacts. The proof of concept of SFM has been conducted by mimicking conditions close to the mentioned occupational settings through the use of a low computational power algorithm. The proposed system showed promising results by returning values in agreement with the reference system mimicking RR in a wide range of values.