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Updated: Dec 15, 2025

Manufacturing Simple and Inexpensive Soil Surface Temperature and Gravimetric Water Content Sensors
Published on: December 21, 2019
Characterization of Low-Cost Capacitive Soil Moisture Sensors for IoT Networks
Pisana Placidi1, Laura Gasperini1, Alessandro Grassi1
1Dipartimento di Ingegneria, University of Perugia, via G. Duranti, 93, 06125 Perugia, Italy.
Abstract:
The rapid development and wide application of the IoT (Internet of Things) has pushed toward the improvement of current practices in greenhouse technology and agriculture in general, through automation and informatization. The experimental and accurate determination of soil moisture is a matter of great importance in different scientific fields, such as agronomy, soil physics, geology, hydraulics, and soil mechanics. This paper focuses on the experimental characterization of a commercial low-cost "capacitive" coplanar soil moisture sensor that can be housed in distributed nodes for IoT applications. It is shown that at least for a well-defined type of soil with a constant solid matter to volume ratio, this type of capacitive sensor yields a reliable relationship between output voltage and gravimetric water content.
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