Photoresistor LDR Sensor Module

The Photoresistor LDR Sensor Module is a beginner-friendly and practical ambient light sensor module designed for microcontroller-based electronics projects. It uses a CdS LDR, whose resistance changes with light intensity: resistance falls in bright light and rises in darkness. The onboard signal conditioning circuit converts this light-dependent resistance change into outputs that can be read directly by popular development boards such as Arduino UNO, Nano, ESP32, ESP8266 and Raspberry Pi Pico. This common 4-pin LDR light detection module provides an analog output for measuring relative light level and a digital output for threshold-based light/dark switching. The digital trigger level can be adjusted using the onboard preset potentiometer, making it convenient for automatic lamp control, dusk-to-dawn switching and security projects without writing complex calibration code. The module typically operates from 3.3V to 5V DC, so it can be used with both 5V Arduino boards and 3.3V IoT controllers. For analog sensing, connect AO to an ADC pin and read changing voltage as the ambient light changes. For simple switching, connect DO to a digital input and adjust the potentiometer until the output changes state at the required brightness. Pin labels are generally VCC, GND, DO and AO; always check the silkscreen on the supplied board before wiring. Ideal for students, makers, hobbyists and product prototyping, this LDR sensor module is useful in automatic night lights, solar garden lamp controllers, smart street light demos, room brightness logging, camera/lighting triggers and light-based robotics experiments. Package includes one Photoresistor LDR Sensor Module; connecting wires and controller board are not included.