LM393 Light Sensor – Detect Light Intensity with Analog and Digital Output

Adjustable Photoresistor Module for Automatic Lighting, Robotics and Monitoring Systems

This LM393 photosensitive sensor module combines a Light Dependent Resistor (LDR) with an LM393 voltage comparator to provide both digital and analog outputs for detecting ambient light intensity. It’s ideal for Arduino, ESP32, Raspberry Pi and other microcontroller projects involving light sensing and automatic controls.

 Key Features

• Operating Voltage: 3.3 V – 5 V DC – standard logic levels.

• Sensor Type: LDR (Light Dependent Resistor) – changes resistance with light level.

• Comparator: LM393 provides a stable digital output based on a set threshold.

• Dual Output:

  • Digital Output (DO): HIGH or LOW depending on whether light intensity crosses the threshold.

  • Analog Output (AO): Continuous voltage proportional to light level (available on 4‑pin versions).

• Adjustable Sensitivity: Onboard potentiometer to fine‑tune the trigger level.

• Indicator LED: Shows module status and output.

• Pins: VCC, GND, DO, (AO) interface for simple connections.

• Compact PCB for integration into various projects.

 Overview

The LDR’s resistance varies with light intensity. The LM393 comparator compares the LDR signal to a reference and outputs a digital HIGH/LOW signal, making it suitable for light‑activated switches and detectors. When used with the analog output, you can also read light levels more precisely using a microcontroller’s ADC.

 Typical Uses

• Automatic lighting systems controlled by ambient light.

• Smart home and IoT applications responding to light changes.

• Security systems detecting light interruptions.

• Robotics and sensor projects needing light detection.

• Educational electronics and prototyping. 

1.Using sensitive photosensitive resistance sensor.

2.The comparator output signal is clean, good waveform, driving ability, more than 15mA.

3.With adjustable potentiometer to adjust the brightness of the light detection.

4.The working voltage 3.3V-5V.

5.The output form: DO digital switching outputs (0 and 1) and AO analog voltage output.

6.A fixed bolt holes for easy installation.

7.PCB Size: 3.2cm x 1.4cm.

8.Using a wide voltage LM393 comparator.