The photosensitive resistor module is most sensitive to ambient light, is commonly used to detect the brightness of ambient light, which triggers microcontrollers or relay modules; When the module's ambient light brightness reaches the set threshold, the DO side outputs a high level when the ambient light level exceeds the set threshold, the DO side outputs a low level; DO output can be directly connected to the microcontroller to detect high and low signals, thus detecting changes in ambient light intensity; Our DO outputs can directly drive the relay module, which can be composed of a light control switch. Speed range from 0% to Feature: Uses the sensitive type of photosensitive resistance sensor Comparator output clean waveform is good, driving ability, than 15mA. With adjustable potentiometer, you can adjust the brightness of the detected light Working voltage 3.3V-5V Output format: Digital switch output (0 and 1) With bolt holes for easy installation A small circuit board PCB size: (L*for B)3.20 x 1.40cm/1.26"*0.55" Uses a wide voltage LM393 comparator Quantity: 1Pc Product Connection Details: VCC connect power supply positive 3.3-5 v GND connect power supply cathode DO TTL switch signal output AO analog signal output Note: Size for manual measurement, there may be a 0 to 2 cm error, belongs to the normal phenomenon. And due to the difference between different monitors, the picture may not reflect the actual color of the item. Thank you! Package includes: 1Pc x Intensity Sensor Module