The reflectivity of infrared light varies with the color and distance of the reflecting surface. According to this principle, those 2 channels Infrared Reflective Sensor utilizes a TCRT5000 reflective photosensor module to detect color and distance. When a light-colored object approaches, the signal intensity received by the infrared reflective sensor increases and the indicator LED on board turns red. When a dark-colored object approaches, the intensity decreases and the LED turns off.
This sensor is a basic and widely used part in applications such as line-following cars, rotary speed detection, auto data logging on utility meters, or other situations where color or distance contrast is sharp.