LDR light detection sensor module 4-pin — analog and digital output, LM393, Arduino compatible

This 4-pin LDR (Light Dependent Resistor) sensor module combines a photoresistor with an LM393 voltage comparator to deliver both analog and digital light intensity outputs from a single compact board. The digital threshold is user-adjustable via an onboard potentiometer, making it easy to set the exact light level that triggers the digital output — no code changes required. It is compatible with Arduino, ESP32, Raspberry Pi, and any 3.3V or 5V microcontroller.

Key Specifications:

• Sensor type: LDR (photoresistor / light dependent resistor)
• Comparator IC: LM393 dual differential comparator
• Supply voltage: 3.3V – 5V DC
• Output: Analog (AO) + Digital (DO) threshold output
• Digital threshold: adjustable via onboard potentiometer
• Digital output logic: LOW when light detected (above threshold), HIGH in darkness
• Onboard LEDs: power LED + digital output status LED
• Connector: 4-pin header (VCC, GND, DO, AO)
• Dimensions: ~32mm × 14mm

Pinout:

• VCC: 3.3V – 5V power input
• GND: Ground
• DO: Digital output (HIGH/LOW based on threshold)
• AO: Analog output (voltage proportional to light intensity)

How to Adjust Threshold:

• Turn the onboard potentiometer clockwise to increase sensitivity (triggers at lower light levels)
• Turn counterclockwise to decrease sensitivity (triggers only in brighter light)
• The status LED turns on when the digital output is active (light detected above threshold)

Compatible With:

• Arduino Uno, Nano, Mega (AO to analog pin, DO to digital pin)
• ESP32 and ESP8266 (AO to ADC pin, DO to GPIO)
• Raspberry Pi (DO to GPIO; AO requires external ADC)
• Any 3.3V or 5V microcontroller

Applications:

• Automatic street and garden lighting control
• Day/night detection for IoT devices
• Light-triggered alarms and notifications
• Solar panel sun-tracking systems
• Photography ambient light metering
• Smart home light automation