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Controlling Physical Information

Computers and sensors can be used to control conditions in lots of different places. You might have sensors in your home to control the lights. When light sensors detect that it is dark outside a computer can instruct the lights in your driveway to switch on.

Different types of light sensors (below)

Traffic lights are another example. A computer responds to sensors on a camera, checking to see if cars are waiting. If they are, the lights are changed according to a set pattern. These are simple programmed actions in response to external changes.

An infrared sensor

A good sensor obeys the following rules:

  • it is sensitive to the measured property
  • it is insensitive to any other property likely to be encountered in its application, and
  • it does not influence the measured property

Read more about sensors here: