Keep Your Plants' Lungs Moist Buy Now

Relative Humidity (RH) Sensor

Relative Humidity (RH) Sensor Details

Your plants breathe just like you do.

When humidity levels drop too low, the plants transpire (breathe) faster than nutrients can be transported. Since only water is transpired, nutrients become overly concentrated. Depending on the plant and their growing phase, plants need a relative humidity range between 40% to 70%. The flowering range is usually lower than the vegetative growth stage. For example, cannabis is optimally grown indoors at 50% to 70% during vegetative growth, and 50% to 60% while flowering.

Our air humidity sensors, can help you achieve the optimal relative humidity for your plants. The VG-HUMID is a low-cost, low-power, precision relative humidity (RH) sensor, for measuring relative humidity of air.

Rugged Water Resistant Case

The sensor and electronics are enclosed in a weather resistant flanged box for easy mounting. The electronic sensor is directly connected to the outside air through a small inlet tube, on the bottom side of the box near the cable gland. Because the small inlet tube isolates the sensor from the rest of the air volume in the box, latency to changes in relative air humidity is reduced.

Simple 3 Wire Interface

The sensor has a simple electrical interface of 3 wires: ground, power and an analog output voltage which is linear and directly proportional to the relative humidity ranging from 0 to 3.0V, where 0 represents 0% humidity and 3.V represents 100% humidity. It can be powered with a voltage supply from 3.5V to 20V, and consumes less than 11 mW (3.4mA at 3V).

When ordering this relative humidity (RH) sensors, you can select the length of the power cable in standard 2 meter, 5 meter or 10 meter lengths. The sensing cable comes in the standard lengths of 1 meter and 3 meter lengths. See the ordering table below.

Vegetronix Agricultural Building Blocks

We provide modular building blocks that you need to create your agriculture application. With these building blocks, you can create systems that will monitor light levels and control lights and valves based on the readings.

For recording data, we carrier simple low-cost data loggers, which can read up to 8 sensors. Waterproof wall mountable displays allow you to see your sensor data, near its source.

For remote viewing of data, we provide a WiFi Data Logger, which will read up to 4 sensors, and store data in the cloud. This Sensor Hub lets you remotely view your sensor data on your phone's web browser. You can even receive text messages, and email alerts.

We've partnered with the sensor cloud site - which will graph, store, and manage your air humidity data.

We Want you to be Happy

Ordering is easy and low risk. Since we build our own products at our factory, all of our products are in stock. When you place your order from our website, it will ship same day from our factory, and you'll have it in your hands in just a couple of days. We ship to nearly EVERY COUNTRY in the world.

If you aren't amazed and delighted by your new VG-HUMID Relative Humidity (RH) Sensor, return it for a refund within 30 days.

Relative Humidity Sensor Features

  • Low cost.
  • Output Voltage is proportional to relative humidity.
  • Rugged design for long term use.
  • Compact size.
  • Very low power operation.
  • Precise measurement.
  • Wide supply voltage range (3.5 to 20VDC).
  • Weather resistant enclosure.
  • Compatible with Arduino.

Relative Humidity Sensor Applications

  • Crop Steering.
  • Optimize plant transpiration.
  • Weather and Environmental Monitoring.
  • Greenhouse Automation.
  • Aquaponics.
  • Monitoring of Terrariums.
  • Sensor for Internet of Things.

Relative Humidity Sensor Pricing and Ordering Info

We ship to nearly EVERY COUNTRY on the planet, directly to you from our factory.

99% of orders ship same day.

Part Number Description Price Purchase
VG-HUMID-2M Relative Humidity Sensor with 2m Power Cable Buy Now
VG-HUMID-5M Relative Humidity Sensor with 5m Power Cable Buy Now
VG-HUMID-10M Relative Humidity Sensor with 10m Power Cable Buy Now

Contact us for volume pricing information.

Relative Humidity Sensor Specifications

Power consumption (Normal Mode) 10.2 mW
Supply Voltage 3.5V to 20 VDC.
Dimensions See drawing below.
Power on to Output Stable 500 ms
Output Impedance 10K ohms
Operational Temperature -40C to 85°C
Accuracy at 25°C 3% from 20 to 80 RH,
4.5% from 0 to 20 RH, and 80 to 100 RH.
Resolution 0.1% RH
Output Range 0 to 3V linear with relative humidity.
Voltage to RH equation RH(%)= V*33.33

Relative Humidity Sensor Drawing

Relative Humidity Sensor
VG-HUMID Relative Humidity Sensor Enclosure Drawing

Relative Humidity Sensor Wiring Table

Terminal Block 1 Wire Color Description
Pin 1 Red POWER: 3.5V to 20 VDC.
Pin 2 Black OUT: (0 to 3V linear with relative humidity.)
Pin 3 Bare Ground

Frequently Asked Questions - FAQ

  • Is the box water proof?
    • The enclosure is a water tight box with a gasket on the parting surface between the box and lid, however, to measure relative humidity, the sensor needs access to the air which it is measuring, so it has a small hole in the enclosure next to the cable gland to allow air to enter into the box. The box should be mounted with the cable gland facing downward so that rain or other water can not flow into the box.
  • What to I get when I order a VG-HUMID relative humidity sensor?
    • It includes: a sensor board, power cable, and weather resistant box.
  • How should the enclosure be mounted?
    • Mount the cable gland facing downward.

How to Get Started with the Relative Humidity Sensor

The best way to get started is to purchase a few low cost relative humidity sensors from our webstore and try them out in your application.

Buy Now