Relay Board for Switching Pumps and Valves Buy Now

Pump and Valve Relay Switching Board

The VG-RELAY-DC board is perfect for controlling traditional sprinkler valves, pumps, or interfacing to other control systems. It interfaces directly to Vegetronix soil moisture sensors. Because it uses a 5A mechanical relay, it can directly control higher power AC or DC devices. It has 2 LEDs to indicate that the board has power, and the on/off state of the relay.

The VG-RELAY-DC board interfaces to a single VH400 soil sensor, and can activate a high power AC or DC load such as a valve or alarm, or other control device, when a moisture level is reached. The threshold is easily set with the onboard variable resistor, and a small screwdriver. The relay board can be configured with a jumper to turn the relay on when the sensor detects wetness or on when the sensor detects dryness.

The VH-RELAY-DC also serves as an evaluation board. If you are thinking about testing our VH400 soil moisture sensors you should consider purchasing this board as well.

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  • Perfect for evaluating our VH400 soil moisture probes.
  • Interruption and control off irrigation and sprinkler systems.
  • Interface soil moisture sensors to home automation systems.
  • Control and monitoring of moisture content in bulk foods.
  • Rain and weather control functions.
  • Environmental control functions.
  • Water conservation applications.
  • Fluid level measurements and control.


  • Powered from a wide range DC supply.
  • Can be configured as a normally open or normally closed contact with a simple jumper setting.
  • Uses a mechanical relay.
  • Can control a 5A 250V load.
  • Interfaces to a single VH400 probe.
  • Low power.
  • LED indicators, indicate power on and relay contact.
  • Terminal blocks for quick connection.
  • Low price.
  • Small size.
  • 4 mounting holes in each corner.

Relay Board Selector Guide

Vegetronix offers a variety of relay boards for nearly every application. See our Relay Board Selector Guide for help in determining which board is appropriate for your application.

Other Vegetronix Products of Interest

Pricing and Ordering Info

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99% of orders ship same day.

Part Number Description Price Purchase
VG-RELAY-DC AC Relay board for the VH400 probes. Interfaces to a single VH400 Moisture Sensor Probe. $39.95 Buy Now

For volume pricing contact us.


Power consumption < 40mA when relay engaged.
Supply Voltage 6V to 24 VDC.
Relay Load 5A at 250VAC maximum load
Dimensions 1.75in by 1.75in
Number of sensor interfaces 1
Number of relay outputs 1

Wiring Table

Pin Description
2 DC input 1 (max 24VDC rms)
1 GROUND: (connect to probe ground - bare wire)
2 SENSE: (connect to probe output - black wire)
3 POWER: 5V (connect to probe power - red wire)
Terminal Block TB3 (RELAY INTERFACE)
1 Relay contact 1
2 Relay contact 2

How to Get Started

The best way to get started is to order a few low cost probes and relay boards and try them out in your application.

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