Non-intrusive vital sign monitoring using an intelligent pillow based on a piezoelectric ceramic sensor

Abstract

Performing real-time monitoring for human vital signs during sleep at home is of vital importance to achieve timely detection and rescue. However, the existing smart equipment for monitoring human vital signs suffers the drawbacks of high complexity, high cost, and intrusiveness, or low accuracy. Thus, it is of great need to develop a simplified, nonintrusive, comfortable and low cost real-time monitoring system during sleep. In this study, a novel intelligent pillow was developed based on a low-cost piezoelectric ceramic sensor. It was manufactured by locating a smart system (consisting of a sensing unit i.e. a piezoelectric ceramic sensor, a data processing unit and a GPRS communication module) in the cavity of the pillow made of shape memory foam. The sampling frequency of the intelligent pillow was set at 1000 Hz to capture the signals more accurately, and vital signs including heart rate, respiratory rate and body movement were derived through series of well established algorithms, which were sent to the user’s app. Validation experimental results demonstrate that high heart-rate detection accuracy (i.e. 99.18%) was achieved in using the intelligent pillow. Besides, human tests were conducted by detecting vital signs of six elder participants at their home, and results showed that the detected vital signs may well predicate their health conditions. In addition, no contact discomfort was reported by the participants. With further studies in terms of validity of the intelligent pillow and large-scale human trials, the proposed intelligent pillow was expected to play an important role in daily sleep monitoring.

Recent Advances in Flexible Multifunctional Sensors

“…Electroceramic materials have high dielectric properties, piezoelectricity, and electromechanical coupling. These characteristics can adapt to environmental changes and realize the mutual conversion between mechanical and electrical energy [17]. For example, the layered lead zirconate titanate (PZT) structure was prepared via freeze-casting, and the polydimethylsiloxane (PDMS) matrix was impregnated in arranged channels to form piezoelectric composites (Figure 2e) [18].…”

Self‐Powered Wearable Piezoelectric Monitoring of Human Motion and Physiological Signals for the Postpandemic Era: A Review

“…Other requirements of piezoelectric materials and composites to be used in self‐powered wearable sensors are favorable mechanical flexibility, biocompatibility with human skin, a simple structure and high accuracy; in addition, they must be quick and easy to set up. Table 3 lists the advantages and disadvantages of piezoelectric sensors based on PZT, [ 23 ] PVDF and its copolymers, [ 41 ] and KNN, [ 53 ] over other sensors.…”

“…In the future, piezoelectric microelectromechanical system (MEMS) devices have a bright market outlook for use in multifunctional wearable devices, allowing motion recognition and monitoring, disease warning, warning if a mask is worn for too long, and so on (Figure 1). [23,24] The materials employed in the diverse range of monitoring devices not only include the most conventional piezoelectric materials, for instance, polyvinylidene fluoride (PVDF), lead zirconate titanate (PZT), and barium titanate (BTO: BaTiO 3 ). Also, novel piezoelectric materials, such as gallium nitride (GaN) thin film, piezoelectric bio e-skin and biomaterials derived from fish skin.…”

“…In the future, piezoelectric microelectromechanical system (MEMS) devices have a bright market outlook for use in multifunctional wearable devices, allowing motion recognition and monitoring, disease warning, warning if a mask is worn for too long, and so on ( Figure ). [ 23,24 ]…”