LM393 Photosensitive LDR Light Sensor Module for Arduino

LM393 Photosensitive LDR Light Sensor Module

Product Description

The LM393 Photosensitive LDR Sensor Module is a compact light-detection module designed to measure ambient light intensity and provide both digital and analog outputs. It uses a sensitive Light Dependent Resistor (LDR) along with an LM393 voltage comparator, making it suitable for Arduino, ESP32, Raspberry Pi, STM32, and other microcontroller projects.

The module can be used for automatic lighting, light monitoring, robotics, security systems, and other applications that require detection of changes in surrounding brightness.

Dual Output Modes

Digital Output (DO)

The digital output provides a HIGH/LOW logic signal based on the light threshold set using the onboard potentiometer. This is useful for trigger-based applications such as automatic lights, alarms, and light-activated switches.

Analog Output (AO)

The analog output provides a continuously varying voltage related to the detected light intensity. It can be connected to a compatible ADC input for monitoring changes in brightness.

Adjustable Sensitivity

An onboard blue precision potentiometer allows the user to adjust the light detection threshold. This makes it possible to configure the module according to the required brightness level for a specific application.

Status Indicators

The module includes a Power LED and a Digital Output Status LED, allowing users to quickly verify power and observe digital trigger activity during testing and calibration.

Key Features

• LDR-based light detection
• LM393 voltage comparator
• Digital and analog outputs
• Adjustable light sensitivity
• 3.3V–5V DC operation
• Power and output indicator LEDs
• Compact PCB design
• Mounting hole for easy installation
• Compatible with Arduino, ESP32, Raspberry Pi, and STM32

Technical Specifications

Feature	Specification
Main Chip	LM393 Voltage Comparator
Sensor Type	Photosensitive Resistor (LDR)
Operating Voltage	3.3V – 5V DC
Output Type	Digital (0/1) & Analog
Output Current	~15mA
PCB Dimensions	32mm × 14mm × 8mm
Connection	4-Pin Header
Pins	VCC, GND, DO, AO

Working Principle

The LDR changes its resistance according to the amount of light falling on it. The module uses this change to produce an analog signal representing light intensity.

The LM393 comparator compares the detected level with the threshold set by the onboard potentiometer. When the threshold is crossed, the digital output changes state, allowing the sensor to be used as a light-triggered switch.

Interface

The module provides four connections:

• VCC: Power supply
• GND: Ground
• DO: Digital output
• AO: Analog output

Typical Application Scenarios

Smart Home

Suitable for automatic lamps, day/night detection, curtains, and lighting control.

Automotive

Can be used in experimental automatic headlight and light-sensitive control systems.

Robotics

Useful for light-seeking robots, light avoidance systems, and contrast detection.

Security

Can be used for light-sensitive alarms and experimental laser or light interruption detection.

Agriculture

Suitable for sunlight monitoring and greenhouse automation projects.

Applications

• Automatic lights
• Day/night detection
• Light intensity monitoring
• Smart home automation
• Robotics
• Security systems
• Light-sensitive alarms
• Agricultural monitoring
• Greenhouse projects
• Arduino projects
• ESP32 projects
• Raspberry Pi projects
• STM32 projects

Package Includes

• 1 × LM393 Photosensitive LDR Light Sensor Module

Product Disclaimer

Product information provided on our website may vary between manufacturers, suppliers, and production batches. Please verify the actual module specifications before using it in critical applications.

Product images are for illustrative purposes only and may differ slightly from the actual product in colour, component placement, or other visual details.

Important Note

Calibration

If the digital output LED remains continuously ON or OFF, gently adjust the blue potentiometer until the output responds correctly to changes in light intensity.

Voltage

The module operates from 3.3V–5V DC. Ensure the supplied voltage is within the specified range.

Analog Output

When using the analog output with a microcontroller, ensure the output voltage is compatible with the ADC input range of the connected controller.

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