| Pin | Name | Function |
|---|---|---|
| 1 | VCC | Power supply |
| 2 | GND | Ground |
| 3 | AO | Analog moisture reading |
| 4 | DO | Digital output (moist/dry threshold) |
Summary
Two-part module — a probe that goes into soil, plus a small board that reads it. Gives both an analog reading (how moist the soil is) and a digital on/off signal (moist or dry, threshold set by an onboard trimpot). This covers the common cheap resistive version; capacitive versions (which corrode less) exist too and are wired the same way.
- Type: Resistive (LM393-based comparator board)
- Supply voltage: 3.3V - 5V
- Output: Analog (AO) + digital threshold (DO)
- Threshold adjustment: Onboard potentiometer