Soil moisture sensor with Arduino
Soil moisture modules are a simple and friendly way to check how wet your soil is using a pair of probes and a small control board. They offer two outputs you can use with Arduino: an analog signal that changes depending on how wet the soil is, and a digital signal that flips on or off when the moisture crosses a level you set with the onboard potentiometer. The whole setup is compact, cheap and very popular for plant care projects, garden automation and basic hobby experiments.