Forked Finger Electrode Based Acquisition Circuit and Humidity Correlation Model Design

Abstract

With the continuous development of industry, humidity sensors have long been used in many fields such as industrial and agricultural production, public meteorological services, and medical fields. Humidity is a very important environmental parameter that has an impact on production, health and comfort in many fields. Conventional humidity sensors usually use capacitive or resistive measurement principles, which are not very sensitive and accurate to meet the needs of certain high precision and high sensitivity measurements. In addition, high-precision and high-sensitivity humidity sensors are usually expensive, which limits their use in certain applications. First, this paper designs a humidity acquisition hardware circuit based on forked-finger electrodes by taking advantage of their high sensitivity. Second, the data tested by the constant humidity chamber method and the saturated solution method are compared to select a suitable method for the humidity testing environment. Finally, the humidity correlation model design was carried out based on the least squares method. Thus, the humidity sensor based on the forked finger electrode obtained by the design can test the humidity in the environment easily and quickly, and the correlation model of the relative humidity-forked finger electrode capacitance value is obtained at the same time. By evaluating the model and calculating the error between the theoretical capacitance value and the actual capacitance value, it can be concluded that the model is a more reliable model within the error range without overfitting and underfitting problems. In turn, the problem of low sensitivity and high cost of the current humidity sensor can be well solved, providing a basis for relevant academic research and practical applications.