The soil moisture sensor module , built around the LM393 comparator, gives an active-low (L) level output when the soil is dry (determined by a pre-setted threshold value). This digital output (wet ...

It uses Arduino Duemilanove microcontroller board. Two wires placed in the soil pot form a variable resistor, whose resistance varies depending on soil moisture. This variable resistor is connected in ...

My soil-moisture reading was in the low 700s in soil that had around 30 percent moisture (according to a comparison with a commercial soil-moisture sensor), and 661 in a drier pot.