KY-018 Photoresistor LDR Sensor Module

The KY-018 is a compact and easy-to-use light-sensing module built around a Light Dependent Resistor (LDR), also known as a photoresistor. As ambient light levels change, the resistance of the LDR varies inversely — outputting a higher analog voltage in darkness and a lower voltage in bright light. This analog signal can be read directly by any microcontroller equipped with an ADC pin, including Arduino, ESP8266, ESP32, and STM32 boards.

Featuring a simple 3-pin interface for signal, power, and ground, the KY-018 requires no additional components or complex wiring to get started. It is fully breadboard compatible and integrates effortlessly into existing development setups.

Typical applications include automatic light control systems, ambient light monitoring, smart home automation, security systems, and display brightness adjustment. It pairs excellently with relays, LEDs, or LCD displays for responsive light-triggered projects.

Affordable, reliable, and beginner-friendly, the KY-018 is an essential sensor module for any electronics enthusiast or maker.

Specification:

• Sensor Type : Light Dependent Resistor (LDR)
• Interface : Analog (ADC)
• Operating Voltage : 3.3V – 5V DC
• LDR Resistance (Dark) : 1MΩ (typical)
• LDR Resistance (Bright) : 10KΩ (typical)
• Output : Analog Voltage
• Pins : 3 (Signal, VCC, GND)
• Compatible Boards : Arduino, ESP8266, ESP32, STM32
• PCB Dimensions : 15 × 36 mm