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 ...

This variable resistor is connected in a voltage divider configuration, and Arduino collects a voltage proportional to resistance between the 2 wires. Insert the 2 probes (wires, pcb) in the dry soil ...

Personally, I like the use of an ATMega328P here, because it’s the base of the Arduino Uno and readily available. Being available in DIP form factor also means that the Arduino can be built from ...

Using an Arduino, a moisture sensor, an LED matrix, and a few other parts, dr.mcc's build monitors the moisture level in a pot of soil and then lets you know when the plant needs water by ...

In a way, the magic of a soil moisture sensor’s functionality boils down to a simple RC circuit. But of course, in practice there is a bit more to it than that. [rbaron] explains exactly how … ...