Light Meter - Use in Illumination

Use in Illumination

Light meters or light detectors are also used in illumination. Their purpose is to measure the illumination level in the interior and to switch off or reduce the output level of luminaires. This can greatly reduce the energy burden of the building by significantly increasing the efficiency of its lighting system. It is therefore recommended to use light meters in lighting systems, especially in rooms where one cannot expect users to pay attention to manually switching off the lights. Examples include hallways, stairs, and big halls.

There are, however, significant obstacles to overcome in order to achieve a successful implementation of light meters in lighting systems, of which user acceptance is by far the most formidable. Unexpected or too frequent switching and too bright or too dark rooms are very annoying and disturbing for users of the rooms. Therefore, different switching algorithms have been developed:

• difference algorithm, where light switch on lower light level than they switch off, thus taking care that the difference between the light level of the 'on' state and 'off' state is not too big
• time delay algorithms:
  • certain amount of time must pass since the last switch
  • certain amount of time of sufficient illumination.