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Definition of a Light Sensor

The light sensor is a unique tool that can come in handy for numerous uses such as measuring objects and detecting objects. The tool is used in labs for scientists, in offices for the general work force and in home security systems.


A light sensor is a mechanical device sensitive to light, temperature, radiation level, that transmits a signal to a measuring or control instrument, according to Dictionary.reference.com. Similar to how the human eye is sensitive to light and body hair is sensitive to nearby objects, the light sensor is a tool that is sensitive.


This instrument can be used to give information on distance, shape, speed, dimensions and types of substances contained in various objects, depending on the area of study it is being used for. With a high level of precision, they are used for measuring purposes in architecture and offset printing. (A type of printing process used by large commercial printers. The ink doesn't press directly on the paper, it is distributed from a metal plate to a rubber mat where it then proceeds to the paper.)

Other Uses

The general public knows light sensors best when they are used in motion detector devices. Whenever a porch light or a burglar alarm goes off (or is activated), the light sensor within the device has just been used. When an object has entered the field of view of the light sensor, an electrical impulse will activate the bulb or the alarm, proving that the light sensor is sensitive to whichever object entered its view.

Printing and Filming

In printing and film extrusions for web-based operations, light sensors can function to halt a machine if it is in danger of breaking the roll of paper or film. This is beneficial because in the end it may result in less downtime of fixing the machine and getting it to run properly again. When the roll (or web) breaks, a light sensor (usually positioned close to the web) senses the difference of light and will trip an automatic shutoff switch within the machine.

Light Sensors in Space

The mechanical tool is also very much used in space exploration. It can make topographical maps of planetary surfaces and other various celestial bodies. The light sensor is used to gather the information required to resolve the inquiry when it detects any forms of light from stars, planets, comets and other outer space objects

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