RE: Light level monitoring - to add to Homevision/Comfort

["Gary Tall" <gtcs@xxxxxxxxxxxxx>]

Thanks Kevin. I don't have any of the internal C-Bus PIR's (SWMBO
didn't
want too many things visible on the interior).



It is a good call though as I do have six of the external PIR's though
around the exterior of the house. It's a long while now since I've opened
the C-Bus Toolkit but it appears they have a sunset/sunrise feature too. It
looks like I could create a phantom light group for each of these and use
the state of these to determine whether the lights should turn on on/off in
the appropriate rooms.



I need to have another look though as I can see how I turn the phantom
light
on at "sunset" but not how to turn it off at "sunrise"



Thanks

Gary



From: ukha_d@xxxxxxx [mailto:ukha_d@xxxxxxx] On Behalf Of
Kevin Hawkins
Sent: 26 May 2012 13:54
To: UKHA Group
Subject: Re: [ukha_d] Light level monitoring - to add to Homevision/Comfort






>
> Hi Gary,
>
> Is it inside or outside that you wish to monitor ? Do you already have
> by any chance any of the C-Bus sensors with inbuilt light level
> reporting ? Some of the ceiling PIR's include this as a bonus feature
> (5753PEIRL), you never know, you might already have something.
>
> I'd need to check about support within the xAP gateway for these -
> can't remember if they can report or at least control via a lighting
> compatible application or if they're on measurement. I think they are
> compatible as they can be used without logic to achieve much the
> effect you want.
>
> I have played with this and it took a bit of refining to get it
> working acceptably. I use sensors within the room now (xAP reporting
> but IDRANet hardware not C-Bus ) and also have outside light level
> reporting. The lights can vary in brightness to maintain an inside
> minimum lighting level but in practice they were mostly on/off in the
> not brightly illuminated room. Ramp times reduced the switching
> annoyance. I also had to set up some logic to avoid this happening
> when unoccupied and/or at weird times like at dawn if it got brighter
> and then darker again. Hysteresis was important too and I found that
> the lights were not sufficiently bright to avoid the room going a lot
> dimmer in overcast periods. I think you need a lot of reserve
> brightness (wattage) to actually maintain a constant brightness if
> that's your goal.
>
> Here's a couple of graphs for yesterday .. one inside and one
> outside. The shape of the curves is quite different and I was
> surprised how steep the outside light changes were. If you look
> closely on the inside graph at around 8.30PM you'll see the very small
> difference the lights coming on made in their overall contribution,
> but this was in more of a mood lit room (i.e. dimmer lighting).
>
> Inside http://tinyurl.com/ch8qu3m
> Outside http://tinyurl.com/cx4cfhq
>
>
> K
>





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