12V Soil Moisture Sensor Relay Control Module

12V Soil Moisture Sensor Relay Control Module offers a powerful and automated solution for controlling irrigation systems, pumps, or valves based on real-time soil humidity. This integrated module combines a high-sensitivity capacitive or resistive soil moisture sensor probe with a robust 12V relay, allowing it to directly switch high-power AC or DC loads when soil conditions cross a user-defined threshold. Consequently, this design simplifies the creation of self-watering setups and environmental monitoring projects by eliminating the need for an external microcontroller in many basic applications. Users can easily adjust the sensitivity and trigger point using the onboard potentiometer, which makes it highly adaptable to various soil types and plant needs. Furthermore, the inclusion of both Normally Open (NO) and Normally Closed (NC) relay contacts provides crucial flexibility when connecting different types of actuators to the system.

Key Features:

• Integrated Relay: Features an onboard 12V relay capable of switching loads up to AC 250V 10A or DC 30V 10A, eliminating the need for external driver circuits.
• Adjustable Sensitivity: Users easily adjust the humidity trigger point using the onboard precision potentiometer, which sets the exact moisture level for relay activation.
• High Compatibility: Operates directly from a 12V DC power source, making it ideal for solar-powered or standard battery-operated systems.
• Status Indicators: Includes two LED indicators, one for power status and a second for relay activation status, which provides therefore immediate visual feedback on the system’s state.
• Flexible Output: Provides both Normally Open (NO) and Normally Closed (NC) contacts, offering versatility in load control setup.

Technical Specifications:

• Operating Voltage (V_CC): DC 12 V
• Quiescent Current: ≈ 5 mA
• Activation Current: ≈ 40 mA (When relay is ON)
• Relay Load Capacity: AC 250 V / 10 A or DC 30 V / 10 A
• Detection Type: Soil Moisture (Resistive or Capacitive probe, depends on specific model variation)
• Control Output: SPDT (Single-Pole, Double-Throw) Relay
• Module Dimensions: ≈ 50 mm x 26 mm

Mechanical Specifications:

• Board Material: FR-4 Fiberglass PCB
• Mounting Holes: Features two mounting holes for fixed installation.
• Connection Terminals: Screw terminals for power input and load switching contacts.
• Sensor Interface: 2-pin or 3-pin connector for linking the external soil probe.

Dimensions:

• Module Length: ≈ 50.0 mm
• Module Width: ≈ 26.0 mm
• Mounting Hole Diameter: ≈ 3.0 mm
• Sensor Cable Length: Varies, typically ≥ 20 cm

Pinout and Wiring:

• VCC (Power Input): Connect to the positive terminal of the 12V DC power supply.
• GND (Ground): Connect to the negative terminal of the 12V DC power supply.
• S (Sensor Input): Connects to the external soil moisture probe via cable.
• COM (Relay Common): Connect to the power source line of the load (e.g., V+ or AC line).
• NC (Normally Closed): The relay contact stays closed when the soil is dry and opens when the module detects moisture (relay is activated).
• NO (Normally Open): The relay contact stays open when the soil is dry and closes when the module detects moisture (relay is activated).

Datasheet Reference:

• Download Soil Moisture Sensor Relay Module Datasheet

Commonly Used in:

• Automated Irrigation Systems: Forming the core trigger mechanism for self-watering pots, gardens, and greenhouses.
• Hydroponics/Aquaponics: Monitoring and controlling water circulation pumps or nutrient delivery systems.
• Agricultural Monitoring: Providing simple, local control for small-scale crop and plant maintenance.

Applications:

• Smart Garden Control: Automatically turns on a 12V water pump when soil humidity drops below the set point.
• Moisture Alarms: Triggers an audible or visual alarm (connected via NO/NC contacts) if the soil becomes too dry or too wet.
• Environmental Testing: Serves as a standalone soil moisture data logger trigger. However, this requires additional logging hardware.
• Water Level Sensing: In essence, you can use the probe contacts to detect low water levels in reservoirs, triggering a refill pump.

Equivalent Models:

• 5V Soil Moisture Sensor Module: A lower voltage version offering similar functionality, requiring only a 5V power supply.
• XH-M214: A specific model variant featuring a digital display for the moisture value, although it uses a slightly different interface.
• Capacitive Soil Moisture Sensor + External Relay Board: A two-piece setup providing the same control capability but with separate components.

Package Includes:

• 1 x 12V Soil Moisture Sensor Relay Control Module
• 1 x Soil Moisture Sensor Probe (Resistive)
• 1 x Connection Cable for Probe