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Thread: Presence threshold

  1. #1
    Automated Home Sr Member mcockerell's Avatar
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    Default Presence threshold

    I have just about got the hall and landing lighting working the way that we want it (with a fair bit of help from Karam & Vivian), but have come across a small problem:

    The PIR on the landing has been positioned to 'see' all of the bedroom doors, but unfortunately quite often detects movement past the bottom of the stairs, resulting in the landing lights coming on unnecessarily.

    The Idratek controlled hall lighting is configured to come on for a period of time based on presence when it is dark both externally and internally (there are also manually controlled lights in the hall) and this works very well.

    The landing lights were originally configured in the same way, but I have now included an operating period to minimise spurious switching on of the lights. This is not entirely satisfactory - the operating period is currently set as 21:00-08:00, but this means that outside this period the lights do not come on when someone comes up the stairs or moves around the landing even if the landig is dark

    Is there a better way of avoiding false triggering of presence from the PIR so that I can do away with the operating period?

    Thanks,
    Martin

  2. #2
    Automated Home Jr Member
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    Martin,

    I had the same with a DFP seeing outside one bedroom and onto the landing. My solution was very crude involving a tacky substance that was coloured blue.

    Joking aside, can you mask off the PIR with labels cut to suit to see if that helps and then maybe something more suitable and discrete if proven OK?

    Peter.

  3. #3
    Moderator Gumby's Avatar
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    It is possible to inhibit the output of a motion detector from feeding into the presence logic. I use this to inhibit motion detection whilst curtains are being opened or closed.

    You can connect the output of one motion detector to the inhibit of another. So you could try using hall motion to inhibit landing logic. Of course, this also means that there will be times when the landing will not come on since there is coincidental motion in the hall.

    There is a hold-over time from the initial motion detection (you can see this on the green tell-tale LED) before the inhibit clears and the landing will become sensitive again. You'll have to experiment to see if this means that you don't get lighting on the landing when you need it - also depends on what part of the stairs/landing the hall sensor can see.

    I have a similar issue with a bathroom sensor that can "see" into the landing if the door is open. I have experimented with a General logic function to create a 2 second inhibit signal using a monostable, but unfortunately it seems the general logic output cannot be connected to the bathroom motion sensor inhibit.
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  4. #4
    Automated Home Sr Member mcockerell's Avatar
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    Thanks for the suggestions. I don't think that I can mask the sensor so that it doesn't also ignore anyone coming up the stairs - it would use the same part of the lens. Also using the inhibit from the hall sensor means that the lights don't come on until you're at the top of the stairs, which is really too late.

    I too have experimented with the General Logic, trying to gate the input to the landing presence object - unfortunately it's not possible to make this connection.

    At present I'm stuck with an operating period, which isn't very satisfactory.

    Hopefully General Logic will become more flexible in a future version of Cortex.

    Martin

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