Design and Calibration of a Low-Cost SDI-12 Soil Moisture Sensor

Abstract

Water is the main limiting factor in agricultural production as well as a scarce resource that needs to be optimized. The measurement of soil water with sensors is an efficient way for optimal irrigation management. However, commercial sensors are still too expensive for most farmers. This paper presents the design, development and calibration of a new capacitive low-cost soil moisture sensor that incorporates SDI-12 communication, allowing one to select the calibration equation for different soils. The sensor was calibrated in three different soils and its variability and accuracy were evaluated. Lower but cost-compensated accuracy was observed in comparing it with commercial sensors. Field tests have demonstrated the temperature influence on the sensor and its capability to efficiently detect irrigation and rainfall events.

Evaluating the suitability of the consumer low-cost Parrot Flower Power soil moisture sensor for scientific environmental applications

“…While the horizontally installed professional probes show a weaker wetting and drying signal after rain events, causing the autocorrelation curve to be slightly flatter and reaching the e-folding time a few hours delayed. On average an e- folding time of about 3.5 d was estimated by both sensor types, which is in accordance with e-folding times of in situ observations in existing literature (Ghannam et al, 2016).…”

“…rainfall, drought) long after its occurrence is commonly referred to as soil moisture memory (Delworth and Manabe, 1988). Memory timescales of root-zone soil moisture are typically on the order of a week to a few months, depending on soil properties and meteorological variables (Ghannam et al, 2016).…”

“…While commonly being referred to as "low-cost" sensors (e.g. Mittelbach et al, 2011;Bogena et al, 2007;Kizito et al, 2008;Domínguez-Niño et al, 2019;González-Teruel et al, 2019;Matula et al, 2016), deploying them in high numbers and densities is still too expensive. The alternative is to either design and develop a completely new sensor (e.g.…”

“…The alternative is to either design and develop a completely new sensor (e.g. González-Teruel et al, 2019;Kojima et al, 2016), which is a time consuming and challenging task, or make use of existing commercial products, which are not designed for scientific use and are in fact low-cost sensors.…”

Deriving Field Scale Soil Moisture from Satellite Observations and Ground Measurements in a Hilly Agricultural Region

“…The limited number of in-situ observations available has been a limiting factor for the application of such a downscaling approach [26].An appealing solution is offered by low-cost soil moisture sensors, which have gained great attention in the last decade. A large variety of sensors with different measuring techniques and objectives has been developed recently [32][33][34]. In particular, capacitance sensors found widespread use because they are relatively inexpensive and easy to operate.…”