LDR Sensor Module | Light Dependent Resistor Sensor

The LDR Sensor Module is a 3-pin light dependent resistor breakout operating at 5V DC, providing a single digital output that switches HIGH or LOW based on ambient light level, and is directly compatible with Arduino boards. The ldr sensor module 3 pin design is the simplified counterpart to 4-pin LDR modules — it omits the separate analog output pin, providing only VCC, GND, and a digital signal pin, making it a minimal-wiring option when only threshold-based light detection is needed rather than continuous light level measurement.

The ldr light sensor works using the same CdS photoresistor principle as other LDR electronics — the photoresistor’s resistance decreases as ambient light increases, and an onboard comparator circuit converts this resistance change into a clean digital HIGH or LOW signal once the light level crosses a preset or adjustable threshold. For any ldr sensor project requiring simple “light present” or “dark detected” logic — such as automatic lighting triggers, dark-activated alarms, or basic light-sensing toggles — this 3-pin digital-only ldr light sensor module reduces wiring complexity compared to 4-pin analog+digital variants. The ldr sensor arduino connection requires just one digital input pin alongside power and ground.

One practical trade-off: because this module provides digital output only, it cannot measure continuous light intensity levels or log gradual brightness changes — projects requiring light level data logging or gradual dimming response need a 4-pin module with an analog output instead of this 3-pin digital-only variant. Offered by StemVolt, this light-dependent resistor sensor is suitable for builders and enthusiasts creating day-night switching, energy-saving systems, and embedded electronics projects requiring accurate light detection.

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Features:

• 3-pin design simplifies wiring with VCC GND and digital signal only
• CdS photoresistor converts ambient light to digital HIGH/LOW output
• 5V DC operation directly compatible with Arduino digital input pins
• Onboard comparator handles threshold detection without microcontroller calculation
• Minimal 3-wire connection suits beginner light-triggered switching projects

Technical Specifications:

Applications:

• LDR Sensor Module used for Arduino dark-activated alarm trigger build
• College project uses ldr sensor module 3 pin for light switch demo
• Smart home uses ldr light sensor for automatic night light trigger
• Beginner kit uses ldr electronics for basic light detection logic project
• STEM lab uses ldr sensor project for India light-toggle demo build

Package Includes:

• 1 x LDR Sensor Module