XH-M131 12V Light Control Switch Photoresistor Relay Module
Automatic Brightness Detection & Control Module
The XH-M131 Light Control Switch is a smart photoresistor relay module designed for automatic light detection and brightness control. Featuring an adjustable sensitivity potentiometer and 10A relay output, this module automatically activates or deactivates connected loads based on ambient light levels. Perfect for street lights, automatic lighting systems, and various automation projects.
Uses a photoresistor (LDR) for light intensity detection
Features adjustable sensitivity via potentiometer for precise threshold setting
Supports 10A/250V AC and 10A/30V DC load capacity
Technical Specifications
| Parameter | Value |
|---|
| Model | XH-M131 |
| Power Supply | DC 12V |
| Relay Load Capacity | 10A / 250V AC, 10A / 30V DC |
| Quiescent Current | Less than 5mA (before relay actuation) |
| Relay Pull-in Current | Less than 50mA |
| Output Type | NO (Normally Open) / NC (Normally Closed) |
| Indicator LEDs | Red (Power ON), Blue (Relay Active) |
| Protection Features | Optocoupler isolation, reverse polarity protection |
| Probe Length | 300mm (LDR with cable) |
| Dimensions | 53 x 31 x 31mm |
= Key Features =
Adjustable Sensitivity - Potentiometer sets relay activation threshold
10A Relay Output Direct control of highpower loads
NO/NC Terminals - Flexible switching configuration
Optocoupler Isolation - Protects chip from electrical interference
Reverse Polarity Protection - Prevents damage from incorrect wiring
Dual Indicator LEDs - Power and relay status visual feedback
External LDR Probe - Remote light sensing capability
Four Mounting Holes - Easy installation with M3 screws
= Applications =
- Street lighting automatic on/off control
- Night lights and garden lighting
- Corridor and stairway illumination
- Car light control systems
- Advertising sign lighting
- Greenhouse and agricultural lighting
- Security lighting
- Automation equipment
Wiring Guide
| Terminal | Connection | Description |
|---|
| VCC | DC 12V (+) | Power supply positive |
| GND | DC 12V (-) | Power supply ground |
| COM | Common | Relay common terminal |
| NO | Normally Open | Load connected (closed when relay active) |
| NC | Normally Closed | Load connected (open when relay active) |
= How It Works =
- The photoresistor (LDR) detects ambient light intensity
- When light falls below the set threshold, relay activates
- Blue LED illuminates to indicate relay is working
- Connected load (light/device) turns ON automatically
- When light rises above threshold, relay deactivates
- Load turns OFF automatically
Module operates in light-sensitive mode only
In low light conditions, relay pulls in and remains active
Red LED indicates power, Blue LED indicates relay status
Quick Setup Guide
- Connect DC 12V power to VCC and GND
- Connect load to relay output terminals (NO/NC/COM)
- Power on - red LED illuminates
- Adjust potentiometer to set light sensitivity threshold
- Cover LDR probe to simulate darkness
- Blue LED should illuminate and relay activate
Turn potentiometer clockwise for higher sensitivity (darker activation)
Turn counterclockwise for lower sensitivity (brighter activation)
Perform final adjustment at actual installation location
Sensitivity Adjustment
- Clockwise (CW): More sensitive - activates in brighter conditions
- Counterclockwise (CCW): Less sensitive - activates in darker conditions
- Center: Default setting for general applications
Test by covering LDR with hand to simulate darkness
Fine-tune potentiometer until relay activates at desired light level
Avoid over-tightening potentiometer
Why Choose XH-M131?
Automatic light detection eliminates manual switching
Adjustable sensitivity for any environment
10A relay capacity for high-power devices
Optocoupler isolation for circuit protection
Simple wiring and installation
Versatile for home, automotive, and industrial use
√ Works with all 12V DC power sources
√ NO and NC outputs for flexible control
√ Built-in reverse polarity protection
√ External LDR probe for remote sensing
√ Compact and robust design
√ Low power consumption
Safety Precautions
Installation by qualified personnel only
Disconnect power before wiring connections
Do not exceed 10A relay rating
Verify DC 12V supply voltage before connection
Keep away from water and moisture
Ensure proper ventilation
Use appropriate fuse protection
Relay contacts are rated for resistive loads only
For inductive loads (motors), use additional snubber circuit
Avoid exposure to direct sunlight or heat sources
Troubleshooting
No LED indicators - Check DC 12V power supply and polarity
Relay not activating - Adjust sensitivity potentiometer
Relay always active - Turn potentiometer counterclockwise
Relay never activates - Turn potentiometer clockwise
Blue LED on but no output - Check load wiring connections
Erratic operation - Check for flickering light sources near LDR
Ensure LDR probe is positioned correctly for ambient light sensing
Replace photoresistor if physically damaged
What's Included
- XH-M131 Light Control Module
- Photoresistor (LDR) with 300mm Cable
- User Manual
LED Indicator Status
| LED | Status | Meaning |
|---|
| Red ON | Steady | Power connected |
| Red OFF | Off | No power or reverse polarity |
| Blue ON | Steady | Relay active (load ON) |
| Blue OFF | Off | Relay inactive (load OFF) |
The XH-M131 Light Control Switch provides automatic and reliable light sensing control for your projects. With adjustable sensitivity and 10A relay output, it's the perfect solution for automated lighting systems.
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