5V Humidity switch relay module (Blue)

Description

Description

The 5V Humidity Switch Relay Module (Blue) is a complete, self-contained humidity monitoring and control solution that automatically activates or deactivates electrical loads based on environmental humidity levels. Unlike complex sensor systems that require microcontrollers and programming, this module operates as a standalone device — simply apply 5V power, connect your load, adjust the threshold, and the module handles the rest .

At the heart of the module is the high-quality HR202 humidity sensor (housed in a distinctive blue shell), which detects relative humidity in the surrounding environment . As humidity levels change, the sensor’s electrical properties shift proportionally. An onboard LM393 voltage comparator processes this signal against a reference threshold set by the blue potentiometer, providing clean, stable switching without the jitter or chatter associated with simpler designs .

The module features an SPDT (Single Pole Double Throw) relay with screw terminals for COM (Common), NO (Normally Open), and NC (Normally Closed). The relay contacts are rated for 10A at 250V AC or 30V DC, making it capable of switching most common loads directly — from exhaust fans and dehumidifiers to humidifiers, pumps, and ventilation systems .

Key features include a red power indicator LED, a green relay status LED, an onboard potentiometer for precise sensitivity adjustment, and four 3mm mounting holes for secure installation . The compact PCB measures approximately 50mm × 26mm, making it easy to integrate into control panels, equipment enclosures, or project boxes .

This module is ideal for greenhouse humidity control, mushroom cultivation rooms, reptile terrariums, bathroom exhaust fan automation, museum and archive environmental control, wine cellars, and any application where maintaining specific humidity levels is critical. It is suitable for both hobbyist projects and commercial installations requiring reliable, maintenance-free humidity switching.

Features

• HR202 humidity sensor — High-quality, sensitive, and reliable environmental humidity detection

• 5V DC operation — Compatible with USB power supplies, 5V adapters, and Arduino 5V pins

• 10A relay output — SPDT contacts rated for 250V AC or 30V DC loads

• Adjustable humidity threshold — Onboard blue potentiometer for precise set-point configuration

• LM393 comparator — Provides clean, stable switching without jitter

• Dual LED indicators — Red for power, green for relay status

• Standalone operation — No microcontroller or programming required for basic use

• SPDT relay contacts — COM, NO, NC terminals for flexible load wiring (normally open or normally closed)

• Four mounting holes (3mm) — Easy panel or enclosure installation

• Compact form factor — Approx. 50mm × 26mm × 19mm

Technical Parameters