Colour Sensor

Colour Sensor
A colour sensor is a device that detects and measures an object’s or surface’s colour. Color sensors measure the amount of light reflected or transmitted by an object in various wavelength bands. RGB (red, green, blue) sensors detect the intensity of light in the red, green, and blue areas of the spectrum, whereas CMYK (cyan, magenta, yellow, black) sensors measure the intensity of light in the cyan, magenta, yellow, and black regions of the spectrum.
White light is a mixture of three basic colors known as primary colors. They are red, blue and green. These colors have different wavelengths. Combinations of these colors at different proportions create different types of colors. When the white light falls on any surface, some of the wavelengths of the light are absorbed by the surface while some are reflected back based on the properties of the surface material. Colour of the material is detected when these reflected wavelengths fall on the human eye. A material reflecting wavelengths of red light appears as red. The component used to detect colors is the Color sensor.
What is a Color Sensor?
A color sensor detects the color of the material. This sensor usually detects color in RBG scale. This sensor can categorize the color as red, blue or green. These sensors are also equipped with filters to reject the unwanted IR light and UV light. 
Working Principle of Color Sensor
To detect the color of material three main types of equipment are required. A light source to illuminate the material surface, a surface whose color has to be detected and the receivers which can measure the reflected wavelengths.
Colour sensors contain a white light emitter to illuminate the surface. Three filters with wavelength sensitivities at 580nm, 540nm, 450nm to measure the wavelengths of red, green and blue colors respectively.
Package Includes:
1 x Colour Sensor
Specifications
Input voltage
DC 3V-5V
Output frequency voltage
0 ~ 5V
Best detection distance
1cms 
Dimensions 
3 x 2 x 1cms 
Weight 
5 grams