Capacitive Humidity Sensor–Design and Its Application in Measurement Science

A hygrometer is an apparatus that measure humidity. Modern electronic devices use temperature of condensation or change in electrical capacitance to measure humidity difference. Humidity sensors are employed to provide an indication of moisture levels in the environment. To measure moisture level, various technologies are used. A capacitive type moisture sensor consisting of nanoporous thin film of alumina coated in between two parallel gold electrode onto an alumina substrate will be use. A suitable signal signal conditioning circuit has been develop to convert the capacitance change into voltage signal and signal conditioning is done. The capacitive sensing technology as describe in this paper reveals the fact that capacitive technology is increasingly being used in broad range of applications. Humidity sensor plays an important role in process industries and environment control. This work includes various design aspects and the techniques to interface the signal onto a microcontroller. The electronic activity of all sensor is also different which makes the interfacing of the sensors to the microcontroller. Index TermHumidity sensor, parallel electrodes,porous alumina, sol-gel thin film __________________________________________________*****_________________________________________________