Soil Moisture Controller Module Automatic Watering Device Capacitive Soil Moisture Sensor Automatic Plant Watering DIY Electronic Kit Product description: The soil moisture controller detects the soil moisture through the soil moisture sensor (fork-shaped circuit board). The soil moisture sensor is not conductive in the air. After inserting the soil, the more moisture in the soil, the resistance on the two terminals of the humidity sensor. The lower, the greater the resistance. The sensor's signal is connected to the control circuit through the J2 probe interface. The resistor R2 is connected in series on the humidity probe. The change in humidity is reflected as the change in the voltage at the inverting input of the voltage comparator U1A. If it is lower than the voltage at the same input terminal of U1A, the comparator outputs a high level, otherwise the output is low. Flat, capacitor C2 is a stable output signal to prevent the relay frequency from operating when the humidity is detected. The self-locking switch J3 is used to control the action mode of the relay (whether the high-level pull-in relay is outputted in the first leg of U1A or the low-level pull-in relay in the first leg of U1A). Pay attention to the direction when installing the self-locking switch. The self-locking switch has a raised short vertical line on one side that matches the short side of the mounting position on the PCB. Adjustable resistor R3 is used to adjust the humidity control value. The relay output J4 can be used as an electrical switch for some high-power appliances, such as pumps, sprays and other machinery. Thereby achieving automatic control. Light-emitting diode D1 is the control board power supply indication, and D2 is the relay pull-in action indication. Transistor Q1 can be seen as a non-gate. Working voltage:5V DC voltage Load:250V 10A AC or 30V 10A DC (currents below this range can be used); Package includes:1 Set Soil Moisture Controller Module DIY Kit