Wireless soil moisture sensor


Spook's wireless soil moisture sensor measures soil water tension (matric potential) and temperature. Soil matric potential (SMP) is considered the best way for measuring soil water availability to plants as it constitutes the force with which water is held by soil matrix (soil particles and pore space).

The sensor has a thermistor-based temperature too with a range of -40°C to 125°C (-40°F to 257°F). The soil moisture sensor uses a resistive granular matrix element to accurately measure the matric water potential (soil moisture tension) in the soil.

Soil moisture sensor

Soil Moisture Element

The soil moisture element is unique in that it takes its resistive measurement within a defined and consistent internal matrix material, rather than using the surrounding soil as the measurement medium.

This lets the sensor have a stable and consistent calibration that does not need to be established for every installation.

Temperature Element

The sensor also has a temperature element too. The temperature reading is used for temperature compensation of the soil moisture measurements and compensates for different moisture readings as the temperature changes.

Key features

  • Designed for use in hot and freezing temperatures
  • Measurement range of 0 to 240 centibar (cb) or kilopascal (kPa)
  • Made from high grade steel making it corrosion-resistant
  • Internally compensated for commonly found salinity levels
  • Easy to install and use compared to traditional tensiometers

Did you know?

Did you know

The bar is a metric unit of pressure and is defined as exactly equal to 100,000 Pa (100 kPa), or slightly less than the current average atmospheric pressure on Earth at sea level.

The bar and the millibar were invented by the Norwegian physicist and meteorologist Vilhelm Bjerknes. From 1926 to his retirement in 1932 he held a position at the University of Oslo. He was elected a member of the Royal Swedish Academy of Sciences and the Pontifical Academy of Sciences and was a Fellow of the Royal Society. He was awarded the 1932 Symons Gold Medal of the Royal Meteorological Society.

Vilhelm Bjerknes (B: 14th March 1862 – D: 9th April 1951)

Potential uses for wireless AC sensors

  • Irrigation scheduling
  • Water table monitoring
  • Leak detection
  • Agronomy research
  • Environmental monitoring