A nanoforest-based humidity sensor for respiration monitoring

Abstract

Traditional humidity sensors for respiration monitoring applications have faced technical challenges, including low sensitivity, long recovery times, high parasitic capacitance and uncalibrated temperature drift. To overcome these problems, we present a triple-layer humidity sensor that comprises a nanoforest-based sensing capacitor, a thermistor, a microheater and a reference capacitor. When compared with traditional polyimide-based humidity sensors, this novel device has a sensitivity that is improved significantly by 8 times within a relative humidity range of 40–90%. Additionally, the integration of the microheater into the sensor can help to reduce its recovery time to 5 s. The use of the reference capacitor helps to eliminate parasitic capacitance, and the thermistor helps the sensor obtain a higher accuracy. These unique design aspects cause the sensor to have an excellent humidity sensing performance in respiration monitoring applications. Furthermore, through the adoption of machine learning algorithms, the sensor can distinguish different respiration states with an accuracy of 94%. Therefore, this humidity sensor design is expected to be used widely in both consumer electronics and intelligent medical instrument applications.

Survival in a nanoforest of absorbing pillars

“…From a practical point of view, spiky coatings have recently drown significant attention due to the rapid progress in fabrication technology and favorable performance in many applications such as superhydrophobic materials [76], filtration [77,78], sensing systems [79][80][81], selective protein separation [82], to name but a few. At the same time, a theoretical description of their trapping efficiency was still missing, especially in a transient timedependent regime.…”

SnO2-Based Ultra-Flexible Humidity/Respiratory Sensor for Analysis of Human Breath

“…Humidity sensors also play a vital role in human respiratory monitoring. Several diseases such as asthma [8], bronchitis [9], heart disease [10], sleep apnea syndrome (SAS) [11], and pneumonia [12] can be monitored by the changes in respiratory rate and depth.…”

“…To let the users feel comfortable when using the wearable breath monitor, it is important to develop sensors with ultrathin film and high flexibility. Moreover, continuous respiratory monitoring is one of the important parts to detect several types of heart and respiratory diseases [8][9][10][11][12]. Furthermore, breath analysis is also an important tool to detect various kinds of cancer such as that of the lung, breast, prostate, and colorectal [13][14][15][16].…”

Fast and Reversibly Humidity-Responsive Fluorescence Based on AIEgen Proton Transfer

“…Humidity is an interrelated component of human society and plays an important role in industrial production and daily life such as in textile treatment, food preservation, and health maintenance. , To monitor humidity, various types of humidity-responsive systems have been developed for different applications. − Semiconductor sensors, with a short response time and strong compatibility, are widely used in daily life to conduct relative humidity measurements and can be easily incorporated within a highly integrated intelligent humidity sensor system. − Nevertheless, this equipment suffers from complex fabrication, high weight, and the inevitable need for an external power supply. With the development of material science, the determination of humidity through changes in color that can be directly observed by the naked eye has also been attracting increasing attention.…”