Design and development of a sensor prototype for soil moisture measurement: first experimental results

In this paper the design and the development of an innovative soil moisture sensor for agricultural applications is presented; also the first experimental results are illustrated and compared with those deriving by the underlying theory. The basic idea is to excite the soil with seismic waves (both compressional and shear ones) and to measure their velocity of propagation using a transmitter and a receiver that are separated by a known distance. The first encouraging experimental results here presented are obtained using the cross-correlation between the transmitted and the received signal; however repeated measures show a troublesome scattering around the theoretical values. In depth analysis has shown that this scattering is mainly due to the presence of interfering background noise; the authors are currently working to improve the experimental setup to guarantee better results.