Using motion detection and light sensors in office areas

Discussion in 'General Discussion' started by 2SC, Oct 12, 2007.

  1. 2SC


    Oct 10, 2006
    Likes Received:
    Athens, Greece
    I am wondering if it is possible for CIS people to write an application note for how to install and use in most effective way motion detectors and light level sensors in office areas.
    For example, where should I put the light sensor to control right the office light level (with dimmer lights)?
    Of course my friends, your experiences is much appreciated.
    2SC, Oct 12, 2007
  2. 2SC


    Sep 12, 2005
    Likes Received:
    my experience is that.....Hmm.....think before you propose such system :)

    Do it one by one:

    PIR sensor: It should be used in area with little traffic, and aticve traffic! The C-Bus PIR sensors are not too sensitive to pick up little actions like typing and writing in a chair. You need a big moment for it to detect, so in normal office it is a bad idea to rely on the sensor. By the time you type three emails the light would go off. In meeting rooms where you may need dark circumstance for long time (using projectors etc), the Sensor is in "Dark" condition and it will generate a lot of C-Bus traffic. If you have many PIR sensors in an office, that may be a problem. So my suggestion is that you have a few enable sensor button for different area. You may enable the sensors during off hours only for main office, disable all the sensors during main events..etc.

    Light level sensor: positioning of this depend on site. I like it to be near the big windows so it is more affected by outside rather than the light inside. Some people like to have it at the top of the main desk. Just don't have it directly facing any light source should do.

    Combining both items....I think that's your main question. I try not to let the light level sensor controlling on off, and it should be disabled when light is switched off by PIR sensor or switch....
    wanricky, Oct 25, 2007
  3. 2SC


    Apr 6, 2005
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    Light level sensors mounted in the ceiling NEVER work properly. In almost all installations that we work on these kinds of installations have been bypassed or the sensors taped over.

    It simply doesn't work as expected, as the ceriling mounted sensor detects light falling upwards, which has only a scant relationship with the light level on the task (desk).

    No matter what you do, the client will usually be dissatisfied. It is far better to install an energy-efficient lighting installation (which also has the benefits of gaining maximum Green Star points, which small control stystems don't)
    JohnC, Nov 5, 2007
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