LDR Light Sensor Module

LDR Light Sensor Module – Full Description

The LDR Light Sensor Module is a light-sensitive electronic module used to detect the intensity of ambient light. It is based on a Photoresistor (Light Dependent Resistor – LDR) whose resistance changes according to the light falling on it. This module is widely used in light detection, automatic lighting systems, and IoT projects.

It is compatible with Arduino, Raspberry Pi, ESP8266, ESP32, STM32, and other microcontrollers.

🔹 Product Overview

The module consists of:

• 1 × LDR (Photoresistor)

• 1 × LM393 Comparator IC

• 1 × Adjustable Potentiometer

• Digital Output (DO)

• Power and Ground Pins

• Indicator LEDs

The onboard comparator allows the module to provide a digital HIGH or LOW output depending on the light intensity.

🔧 Key Features

• ✅ Operating Voltage: 3.3V – 5V DC

• ✅ Adjustable Sensitivity via Potentiometer

• ✅ Digital Output (DO)

• ✅ Onboard LM393 Comparator

• ✅ LED Indicator for Power and Output

• ✅ Compact Design

• ✅ Easy Interface with Microcontrollers

⚙️ Technical Specifications

💡 How It Works

• In bright light, LDR resistance decreases.

• In darkness, LDR resistance increases.

The LM393 comparator compares the LDR voltage with the reference voltage set by the potentiometer.

• If light intensity crosses the set threshold → Output changes.

• Output pin gives:

  • HIGH (1) or

  • LOW (0)

You can adjust sensitivity using the onboard blue potentiometer.

🔌 Pin Configuration

The module usually has 3 Pins:

• VCC – Power Supply (3.3V–5V)

• GND – Ground

• DO – Digital Output

(Some versions may also include AO – Analog Output)

🛠 Applications

• Automatic Street Light System

• Light-activated Alarm

• Smart Home Automation

• Day/Night Detection

• Solar Tracking System

• Robotics Projects

• IoT Light Monitoring

• Light intensity switching circuits

🛡 Advantages

• Low cost

• Easy to use

• Adjustable sensitivity

• Stable digital output

• Compatible with most development boards

⚠ Important Notes

• Avoid direct exposure to very high-intensity light for long duration.

• Ensure correct polarity while connecting power.

• For analog light measurement, use AO version if required.

📦 Package Includes

• 1 × LDR Light Sensor Module