Low-Cost 3D-Printed Wireless Soil Moisture Sensor

A fully passive, 3D-printed wireless sensor for detecting soil moisture levels is presented in this paper. The sensor comprises a capacitively loaded antenna whose resonant frequency changes in response to soil moisture level. Results show that a variation in soil moisture levels of 20% by weight causes a change in frequency of 16.66 %. A low-cost sensing scheme for large area soil monitoring is proposed in which the sensors are dispersed in the agricultural land and work in combination with unmanned aerial vehicles (U A V s) which record the sensor readings and send the data to a ground station. Calculations show that the sensors can be read by a UAV flying at an altitude of 298 m. Additive manufacturing technique namely 3D-printing has been used for the fabrication of the sensor.