Design of automatic irrigation system based on FDR theory
Ruiqin Zhang · Transducer and Microsystem Technologies · 2014
It is a rapid,simple and reliable method to measure soil moisture content using dielectric property of soil.Based on the principle of frequency domain reflectometry(FDR),the soil dielectric constant can be tested by the travel frequency of electromagnetic waves in soil,and the soil volumetric water content will be obtained.A set of an automatic irrigation system is designed based on FDR.The theory of FDR is briefly introduced,the hardware and software components of the automatic irrigation system are explained.The soil water content information measured by the soil moisture sensor converts to 0 ~ 5 V voltage signal by signal processing,after analog to digital(A/D) conversion,sent to single chip AT89S52,control on-off time of solenoid valve according to output value to realize automatic irrigation and water-saving irrigation.Experiment shows that this system is stable,accurate and sensitive,satisfies the requirements of automatic irrigation.