Soil Moisture Sensor Module

This is the familiar two-pronged soil probe paired with a small comparator breakout board, the pairing that introduced many hobbyists to automated plant watering. The probe measures resistance between its two exposed prongs, which drops as the surrounding soil gets wetter, and the board converts that into both a continuously variable analog voltage and a simple high/low digital signal once an adjustable threshold is crossed. That digital output means it can drive a relay or indicator LED directly without any code at all, while the analog output still gives a microcontroller a proportional moisture value for more detailed logging. It remains a practical, low-cost entry point for a first soil-monitoring or watering-alert project, with the understanding that the exposed prongs will need periodic cleaning or eventual replacement as they sit in wet soil over time.