An Engineer in Wonderland – Alice’s LED ceiling is complete (ish)

ceiling-after-thumb.jpgI am rather proud of this as there cannot be many fully-LED lit rooms in the world yet.

After a year of contemplation, months of designing, weeks of ordering, days of freezing in the workshop, and hours of wiring in the loft….

….. Alice’s led ceiling project is working.

And it is great.

Nine Cree XP-G leds mounted on laser-cut aluminium metal work have replaced a single 22W CCFL and, at last, I can see in my sock draw.

At the moment, the whole thing is powered from a lab PSU providing 20mA to 1A.

Being able to dim lights over this 50:1 range is a revelation.

20mA gives plenty of light to navigate the room by, and I suspect under 5mA would still be enough.

Comfortable reading requires over 500mA.

11 leds will be needed to complete a nice even pattern in the long oddly-shaped room, so two more will soon be on order – you can just see the extra two sets of metalwork already installed in the middle of the ceiling.


ceiling-after-web.jpgBoth photos are taken on the same colur compensation (‘sunlight’), although the camera auto-brighness has removed any possibility of comparing intensity.

What do you reckon?


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Tags: engineer

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  1. Radiocode
    March 17, 2011 11:44

    Do you have a close-up photo of the metalwork? The effect on the ceiling looks great.
    Lee (Radiocode)

  2. 'Alice'
    January 12, 2011 15:28

    The commercial ballast continues to feed some current through the LEDs when it is ‘off’.
    Very dim, probably well under 1mA, but some light.
    It may be a faulty unit or my installation.
    Await news.

  3. 'Alice'
    January 12, 2011 15:28

    You put it well My Kurt, it is part of my entertainment budget – so no s and d* and rock&roll for me for the next month or two – so no change there then…
    BTW, ground fault breakers of the type that compare L and N current are called RCDs over here in the UK – residual current device – I think the IEE ruled in favour of that name because there were many different names for the same device.
    * the things you have to do for sp_m filters

  4. 'Alice'
    January 12, 2011 15:27

    Nice of you ask Mr Kurt.
    And a Happy New Year to you and all.
    There is one LED/fitting, with 9 (soon to be 11) wired in series across the ceiling using 2mm^2 automotive wire.
    LEDs are fairly cool – 4,500K as I remember.
    To make this wiring legal over here, I used a double insulated controller – in this case a lab PSU until I manage to get hold of the proper thing.
    Cost was in the well-I-am-only-doing-it-once region.
    I have not got the paperwork in front of me, I think it has come to about £200 so far.
    Now I have to make a remote control to go with it – with an all-off wall switch to make sure stand-by is zero.

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