Parallax ColorPAL Color and Light Sensor

The Parallax ColorPAL Color and Light Sensor is a miniature color and light sensor which, through its RGB LED, doubles as a color generator. For sensing color, it uses its LED to illuminate a sample, one color component at a time, along with a broad-spectrum light-to-voltage converter to measure the light reflected back. The amount of light reflected from the sample under illumination from each red, green and blue LED can be used to determine the sample's color.