Humidity detection by nanostructured ZnO: A wireless quartz crystal microbalance investigation

In this paper, we present a wireless relative humidity sensor system prototype which based on quartz crystal microbalance (QCM) coated with nanostructured ZnO as sensing element. The wireless QCM sensor system is composed of two parts: the probe based on QCM sensor and the RF receiver. The probe has two functions: to sense and display the frequency signals and to transmit the signals to the receiver. The receiver connected to the personal computer can receive and record the sensor signals. Experimental results indicate that the wireless RH sensor has quite good stability and reproducibility. The interaction distance between the probe and the receiver can be varied from 5 to 300 m. The proposed system is potential to construct the low-cost, real-time online wireless gas sensor system, which can be used to monitor the pollutants in the family and the harsh environment.