A biSensor measures soil moisture using patented modified TDT technology. Unlike most other soil moisture sensors, the biSensor is self calibrating for all soil types and conditions. This means that moisture readings are consistent even in salty conditions or soils with a high pH.

Here is how the biSensor works. A series of electronic pulses are sent along a wire path embedded in the biSensor. The water surrounding the sensor slows the pulses as they move around the biSensor. The biSensor measures the distance between pulses to get an accurate reading. Accuracy is the ability of the biSensor to read true volumetric moisture. Not only are biSensors very accurate, they are extremely repeatable and sensitive as well. They are repeatable due to their ability to display the same value each time the soil reaches the same moisture level and sensitive enough to detect very small changes in soil moisture.