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4 pin LDR (Light-Dependent Resistor) Photosensitive Sensor Module

Original price was: ₵21.00.Current price is: ₵14.00.

46 in stock

The LDR Photosensitive Sensor Module (4-pin) uses a light-dependent resistor to measure ambient light intensity, offering digital and analog outputs for Arduino-based automation projects.

Categories: Basic Electronics, modules, sensors

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Description

The LDR Photosensitive Sensor Module with LM393 Comparator (4-Pin) is a compact, cost-effective solution for detecting ambient light intensity in microcontroller-based applications. Equipped with a light-dependent resistor (LDR), typically a cadmium sulfide (CdS) photocell, the module exhibits photoconductivity, reducing resistance from 10MΩ in darkness to ~100–200Ω in bright light (10–1000 lux). The onboard LM393 dual voltage comparator processes the LDR’s signal, providing a digital output (DO) that switches between HIGH (5V, low light) and LOW (0V, bright light) based on an adjustable threshold set by a 10kΩ blue potentiometer. The analog output (AO) delivers a continuous voltage (0–5V, mapped to 0–1023 on Arduino’s 10-bit ADC) proportional to light intensity, ideal for precise measurements. Operating at 3.3–5V DC (15mA), the module features four pins: VCC (3.3–5V), GND, DO (TTL-compatible digital output), and AO (analog output). A red power LED indicates operation, and a green status LED lights when DO is LOW (bright light), enhancing usability. With a compact PCB (~32x14mm, ~4g) and M3 mounting holes, it’s easy to integrate into projects. Compatible with Arduino, Raspberry Pi (AO requires an ADC like ADS1115), ESP32, and other platforms, the DO pin can drive relays for applications like automatic lighting or alarms, while the AO pin supports light meters or data logging. The module’s sensitivity is adjustable via the potentiometer, though LDRs have a response time of ~20–100ms, limiting use in rapid light changes. This RoHS-compliant sensor is perfect for smart home automation, night/day detection, and educational experiments, especially when paired with components like a 16×2 LCD for displaying light levels. For optimal performance, calibrate the threshold, avoid direct sunlight to prevent LDR saturation, and protect the module from moisture (no IP rating).