Name: Photoresistor LDR Light Sensor Modules - UNIVERSAL CIRCUIT SYSTEM
SKU: UCS-0343
Price: 100.00 BDT
Availability: InStock

The LDR Photoresistor Light Sensor Module is an adjustable, highly responsive sensor board engineered to detect ambient light intensity and brightness levels. Available in both 3-pin (Digital only) and 4-pin (Analog + Digital) variants, this module serves as a versatile interface for translating physical environmental brightness into clean electronic signals that any host microcontroller can easily read.

🌓 Photosensitive LDR & Adjustable Sensitivity

At the base of each module sits a high-quality Light Dependent Resistor (LDR) whose internal resistance drops rapidly when exposed to light.

Precision Comparator: The board incorporates an onboard LM393 voltage comparator chip, providing clean, stable digital signals free of fluctuating logic noise.
Sensitivity Potentiometer: Features a built-in multi-turn potentiometer (3362 blueprint trimpot). By turning the screw, developers can fine-tune the exact ambient brightness threshold required to trigger the digital switch.

📐 3-Pin vs. 4-Pin Variant Breakdown

This product listing offers two specific board configurations to suit different project complexities:

3-Pin Module (3针): Focuses strictly on digital switching logic. It includes VCC (Power), GND (Ground), and DO (Digital Output). The DO pin outputs a high signal when the environment gets darker than your set threshold, acting as an automatic on/off switch.
4-Pin Module (4针): Offers advanced data collection by adding an AO (Analog Output) pin alongside the standard VCC, GND, and DO pins. The AO pin sends a variable voltage signal representing the real-time, exact percentage of light hitting the sensor, allowing for granular tracking.

💡 Visual Status Indicators

For effortless debugging and setup, the module features dual onboard SMD LEDs:

PWR-LED: Lights up continuously to verify the module is receiving stable input power.
DO-LED: Illuminates instantly when the ambient light drops past your set threshold and the digital pin switches active, removing the need for an external multimeter during calibration.

🛠️ Common Applications

Smart Lighting & Infrastructure: Automated streetlights, night lights, and outdoor security porch lights that turn on at dusk and off at dawn.
Solar Energy Systems: Dual-axis solar tracking arrays that follow the sun’s position across the sky for maximized power generation.
Smart Home Automation: Automatic window motorized blinds that close when the afternoon sun gets too bright or open at sunrise.
Display Systems: Screen backlight dimming controls for electronic dashboards, custom clocks, and outdoor digital signage.