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Thread: Light goes off then straight back on!

  1. #1
    Automated Home Sr Member eddr's Avatar
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    Default Light goes off then straight back on!

    Hi All,

    Since yesterday, my landing light is now coming on as it should when picked up by the PIR, but once it goes off it comes straight back on! The landing has short occupied time-out and the light object is set to only come on for 10 seconds after occupancy removed. When I check the occupied state after the light turns back on, it gets set to 'must be occupied'. The reason for the light turning on is occupied, and the PIR says it senses movement at the same time the light goes off?

    Does anyone know what is causing this strange behaviour ? It wasn't happening the day before (The only changes have been adding a module to the bathroom).

  2. #2
    Automated Home Legend Karam's Avatar
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    Could be that the PIR is detecting change of heat due to light switching. What is the relative positioning of the light and PIR and type of light? Was it colder than usual at the time?

  3. #3
    Automated Home Sr Member eddr's Avatar
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    I'd say same temp same as when it was working ok.

    Light is about third of a metre away from PIR.

    Any solution to this? Others dont do the same

  4. #4
    Moderator Kevin's Avatar
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    Does removing the bulb cause it to work correctly (as seen in Cortex) ? If so it would seem to be bulb heat related and you could try a lower wattage or better still a low energy bulb (if it's not on a dimmer).

    K

  5. #5
    Automated Home Sr Member eddr's Avatar
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    Good idea Kev ill try that when I can, probably tomorow!

    I thought Cortex was programmed to take this into consideration though (when lights turn off, pir/light level changing)?

    Anyway to add a delay so when light turns off PIR output is not valid for a set time?

  6. #6
    Automated Home Legend Karam's Avatar
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    Quote Originally Posted by eddr View Post
    I thought Cortex was programmed to take this into consideration though (when lights turn off, pir/light level changing)?
    It does for light level changes but not PIR. Though I've heard of another case of similar symptoms (though in this case when the room was unheated in winter) it is not commonly known for PIRs to trigger when lights are switched - particularly since you need the heat to be perceived to move as well as to change from background. Obviously it may be possible to ignore the PIR trigger just after a switch on but I think it would be better to understand and tackle the cause. Also I'm wondering about why it didn't occur at one point and then did later. Did installing the bathroom module involve anything else relating to the PIR module eg. wiring changes? Also what kind of light is it and what is the geometry of positioning - for example are both light and PIR in ceiling? Is light dimmed or switched?

  7. #7
    Automated Home Sr Member eddr's Avatar
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    Update:

    Seems like I have fixed the problem by changing the bulb as suggested. The bulb that was in there was what I can only describe as the type you'd put in a bedside lamp or something, quite small but high wattage - Now using a energy saving one and havn't had funny behavour since!

    Thanks all, one to remember.... Must of just been unfortunate?

  8. #8
    Automated Home Legend Karam's Avatar
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    Hmm, would still like to get further detail on this. Wouldn't like to just put it down to being unfortunate. I'll perhaps correspond with you by e-mail to get more specifics and investigate at our end so that if we find something specific to avoid then we can provide future advice.

  9. #9
    Automated Home Sr Member eddr's Avatar
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    Karam,

    No problem - Send us an email with all the details you want, happy to help! I can take pictures of where sensors and light is etc.

  10. #10
    Automated Home Ninja Viv's Avatar
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    In a normal room where the PIR is many feet away from the lights the change for the light from on to off should not trigger the PIR. However close proximity may effect the PIR and give a false trigger.

    Update to Cortex 25.2.1

    Create a general logic - Monostable.

    Connect Gate Source A input to Lights - Set Off (Output) connection.
    Connect Gate Output C to Motion Sensor - Block the output (input) connection.
    Set the Monostable period to something suitable e.g. 5 seconds.

    When the Light goes off the monostable will fire and it output will go high for 5 seconds blocking any false trigger of the PIR. Normnal PIR detection will then resume for occupancy detection.

    Viv.

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