Photosensitive Resistor Sensor Module KY-018

The Photosensitive Resistor Sensor Module KY-018 is a small light sensor board built around an LDR (light dependent resistor), whose resistance falls as light gets brighter. The LDR and a fixed resistor on the board form a voltage divider, so the signal pin gives an analog voltage that changes with the light level. Read it with an Arduino or ESP32 analog input to measure brightness or detect day and night.

Photosensitive Resistor Sensor Module KY-018 Specifications

• Sensor: LDR (photoresistor), resistance falls as light increases
• Circuit: LDR with a 10 kΩ resistor as a voltage divider
• Output: analog voltage on the S pin
• Supply voltage: 3.3 V to 5 V
• Pins: 3 (S = signal, middle = VCC, − = GND)
• Format: KY-018 sensor kit module

Photosensitive Resistor Sensor Module KY-018 Applications

• Automatic night lights and street light models
• Detecting day and night in IoT and smart home projects
• Light-seeking robots
• Logging room brightness over time
• Beginner Arduino sensor lessons

What's in the Box

• 1 × KY-018 photosensitive resistor sensor module

Tip: Connect S to an analog pin such as A0 and print the analogRead() value while you cover and uncover the sensor, to see which way the reading moves before you choose a threshold. Check the pin labels on your board before powering it.

Orders placed before 14:00 are ready for pickup the same day. Delivery across Lebanon usually takes 1–3 working days.