LDR Module Photosensitive resistor module most sensitive to environmental light intensity is generally used to detect the ambient brightness and light intensity.
Pin details
VCC ? 3.3V to 5V DC
GND ? Ground
DO ? Digital Output
Features :

LM393 based design
Can detect ambient brightness and light intensity
Adjustable sensitivity (via blue digital potentiometer adjustment)
Output Digital ? 0V to 5V, Adjustable trigger level from preset
LEDs indicating output and power