Calibration of SEN0308 Soil Moisture Sensor for Moisture Monitoring in Vertisol Soil

Abstract

The SEN0308 soil moisture sensor uses the capacitive sensing principle to detect soil moisture by measuring its dielectric constant. This study aims to calibrate the SEN0308 sensor, evaluate its accuracy, and measure the moisture content of vertisol soil. The experimental method was used to compare soil moisture values in the form of ADC values with laboratory measurements. The measured parameters include soil moisture content and sensor calibration. The calibration process involved creating equations and coefficients of determination using Microsoft Excel, which was then implemented in a programming language to convert ADC values into soil moisture percentages. The calibration results showed that sample A experienced dry conditions with an actual moisture content of 12%, with ADC values for sensors I -VI being 2020, 2067, 2081, 2001, 1994, and 2109, respectively. On the other hand, sample G, adding 1500 ml of water, obtained an actual moisture content of 53% with ADC values for sensors I -VI of 164, 157, 200, 190, 208, and 167, respectively. When the calibration process of the SEN0308 soil moisture sensor has been completed, the sensor can measure the moisture content in the soil in percentage (%) format. Each SEN0308 soil moisture sensor has undergone an accuracy measurement using a non-linear regression analysis with a logarithmic (ln) approach, which results in a relationship between the coefficient of determination and the correlation value that is very good.