Soil Moisture

Sensor specifications (Watermark)


Measurement range: 0 ~ 200 cb
Frequency range: 50 ~ 10000 Hz approximately
Diameter: 22 mm
Length: 76 mm
Terminals: AWG 20


The Watermark sensor by Irrometer is a resistive type sensor consisting of two electrodes highly resistant to corrosion embedded in a granular matrix below a gypsum wafer. The resistance value of the sensor is proportional to the soil water tension, a parameter dependent on moisture that reflects the pressure needed to extract the water from the ground. The function of the library readValue returns the frequency output of the sensor’s adaptation circuit in Hertz (Hz). For more information about the conversion into soil water tension look at Appendix 1 of the Agriculture 3.0 Board technical guide.