The capacitive soil moisture sensor research

摘要

To meet the requirements of a large-scale soil moisture monitoring system, this dissertation developed a new type of capacitive soil moisture sensor based on the detection and amplification of the singal peak-to-peak value named PA-1 sensor. PA-1 sensor was calibrated and evaluated under static laboratory conditions. A new type of soil moisture sensor named PA-1 is developed, which is based on the relationship between soil moisture and soil relative permittivity. Circuit design, operating features and exterior design of the sensor are introduced. PA-1 is calibrated in solution samples using the standard calibration method. Calibration experiment results show that PA-1 has a very linear measurement curve. The performance of PA-1 is studied and compared to the widely used Decagon Company's EC-5 capacitive soil moisture sensor. Experiment results show that PA-1 has advantages of high sensitivity, low temperature drift, strong tolerance to electromagnetic interference and low power consumption.