Function:The light sensor enables a robot to detect light. Robots can be programmed to have a specific reaction if a certain amount of light is detected. The light sensor uses a cadmium sulfosolenide (CdS) photoconductive photocell. The CdS photocell is a photo resistor, meaning that its resistance value changes based on the amount of incident light.

Uses: Design a simple tracker that follows the beam of a flashlight, or use a light sensor to help your robot to avoid getting stuck under furniture by making it steer away from shadows. You can even give your robot color vision by putting colored filters on different light sensors!