The Humidity Sensitive Relay Module 5V is a practical and efficient switching solution that automatically controls devices according to the surrounding humidity level. Powered by a standard 5V supply, this module features a built-in relay and an adjustable potentiometer, allowing users to set the desired humidity threshold at which the relay energizes or de-energizes. Its plug-and-play design requires minimal wiring, making it perfect for both beginners and professionals. Common applications include controlling exhaust fans in humid environments, regulating misting systems for plants, or maintaining stable conditions in aquariums and greenhouses. With its compact form factor and reliable operation, this module offers an excellent automation tool for humidity-sensitive projects. Featured By RoboticsBD.
Product Images are shown for illustrative purposes only and may differ from the actual product.
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Features:
Operates on a simple 5V DC power supply.
Adjustable humidity sensitivity via onboard potentiometer.
Relay switching provides reliable ON/OFF control for loads.
Easy-to-use module, no complex wiring required.
Supports a wide variety of automation applications.
Compact and lightweight design for easy installation.
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Applications:
Automatic exhaust fan control in greenhouses and bathrooms.
Humidity-triggered misting systems for orchids and indoor plants.
Aquarium room humidity regulation.
Environmental monitoring and automation projects.
DIY smart home and agricultural humidity control systems.
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| General Specifications |
| Operating Voltage | 5V DC |
| Relay Control | ON/OFF switching based on humidity level |
| Sensitivity Adjustment | Potentiometer (adjustable threshold) |
| Module Type | Humidity-sensitive relay module |
| Applications | Exhaust fans, misting, greenhouse, aquarium, DIY automation |
| Material | PCB with onboard components |
| Shipment Weight | 0.0159 kg |
| Shipment Dimensions | 6 × 4 × 3 cm |
Please allow 5% measuring deviation due to manual measurement.
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Documentation:
Theory of Operation
The humidity sensor on the module is an HR202.
The humidity level trip-point for triggering the relay can be adjusted using the potentiometer on the module. Turning the pot CW increases the humidity trip-point.
When humidity goes over the trip-point value, an LM393 voltage comparator IC turns on a transistor that energizes the relay coil and it switches ON. A green LED is illuminated when the relay is energized.
When the humidity drops below the preset value, the relay switches back OFF. A flyback diode is included on the module in parallel to the relay coil to safely shunt current when the relay coil is de-energized.
The relay has both NO (Normally Open) and NC (Normally Closed) contacts so the module can either be used to energize a load when humidity goes up past the trip-point value such as an exhaust fan in a greenhouse or when it goes down past that level such as turning on a humidifier to increase the humidity.
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Module Connections
POWER
The module requires 5V power and ground to operate. There is a red LED that is lit when power is applied to the module. When the relay is energized, the module draws about 80mA from the Vcc pin.
1 x 2 Header (Power Connections)
- Vcc = Connect to 5V power supply
- GND = Connect to ground of the 5V power supply
LOAD
The output of the relay is rated to switch up to 30VDC at 10A or up to 250VAC at up to 10A (See our notes below about safely switching VDC).
The output is SPDT type with both a NO (Normally Open) terminal and a NC (Normally Closed) terminal relative to the COM terminal. When the relay is de-energized (green LED OFF) the NO-COM is open and the NC-COM is shorted. When the relay is energized (green LED ON) the NO – COM is shorted and the NC-COM is open.
1 x 3 Screw Terminal (Load Connections)
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- Top = Normally Open relay contact – Load is connected to this terminal if it should switch ON when relay is energized.
- Center = Common connection – Connects to AC or DC power source for load that is being controlled.
- Bottom = Normally Closed relay contact – Load is connected to this terminal if it should switch ON when relay is de-energized.
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Package Includes:
1 x Humidity Sensitive Relay Module 5V
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