Automatic fault detection in a low cost frequency domain (capacitance based) soil moisture sensor

•Two techniques were used for measuring the soil moisture based in Frequency Domain Soil Moisture Sensor.•The first used the soil capacitance as part of a low pass filter, measuring the attenuation of a fixed frequency signal.•The other was using the soil capacitance as the controlling component in a variable frequency oscillator.•These techniques provide an automatic way to detect sensor damage that can prevent mistakes in irrigation management.