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Thread: LEDs: Colour temperature from "trichromatic co ordinates"

  1. #1

    Default LEDs: Colour temperature from "trichromatic co ordinates"

    Hey there,
    I'm a new member at this place, but I've heard all about the extensiveness of its info

    I'm looking for some help for buying LEDs for an automotive application.
    The LEDs are meant to be white, with these specifications
    http://cdn.instructables.com/FZX/NZ1...KEXJ.LARGE.jpg
    (is it possible to post pictures in these threads? Sorry for being amateurish)
    I'm sure no one's gonna notice if it's slightly out of these specifications, but it'd be all the better, legal-wise.

    I'm thinking of *perhaps* purchasing these LEDs
    http://www.ledsales.com.au/catalog/i...oducts_id=1013
    Colour bin is supposedly unknown, but colour temperature is ~5000K.
    Would that fall under the above specs?
    What colour temperature would fall under those specs?

    Any advice is welcome
    Thanks in advance

  2. #2
    Retired Administrator Norm's Avatar
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    Default Re: LEDs: Colour temperature from "trichromatic co ordinates"



    Posting photos

    You would need to host the photos and not hotlink from other sites, as in your post above.

    Norm

  3. #3
    Flashaholic* idleprocess's Avatar
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    Default Re: LEDs: Colour temperature from "trichromatic co ordinates"

    Color temperature is a 1-dimensional metric. Color coordinates are a 2-dimensional metric that better specifies the white point. Neither will nail down the true color rendition ability - you need a spectrum chart for that showing power distribution throughout the visible spectrum.

    A Cree product may well lie within those coordinates, but one would have to check the specific color binning of the product.

    Lastly, since you're hinting at an automotive usage, I would tread quite carefully - automotive regulations in most countries are notoriously difficult for hobbyists to comply with short of many years experience in photometrics and a fortune in test equipment lying about.
    I apologize that this letter is so long; I did not have time to write a short letter

  4. #4

    Default Re: LEDs: Colour temperature from "trichromatic co ordinates"

    Thanks for the link, Norm.

    Hm.... right. Quite unfortunate that I do not actually have the specs...
    I hear the cops in my area are concerned mainly with how much the light glares other drivers, more than the brightness and colour.
    The colour is supposedly a hint that the headlights are HID/xenon, commonly used in the HID conversion kits that (more often than not around my parts) are incorrectly adapted to the standard reflectors...

    Thanks

  5. #5
    Flashaholic* idleprocess's Avatar
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    Default Re: LEDs: Colour temperature from "trichromatic co ordinates"

    Quote Originally Posted by Unknown2 View Post
    I hear the cops in my area are concerned mainly with how much the light glares other drivers, more than the brightness and colour.
    Compliance with automotive safety regulations is immensely more complex than that. In addition to color consistency, a manufacturer is required to comply with mechanical and light-distribution requirements that are not easy to meet.
    I apologize that this letter is so long; I did not have time to write a short letter

  6. #6

    Default Re: LEDs: Colour temperature from "trichromatic co ordinates"

    I hear the cops in my area are concerned mainly with how much the light glares other drivers, more than the brightness and colour.
    And your question is.....

    Cops aren't engineers, and they aren't lawyers, and they typically won't argue about DOT regulations nor carry a lux meter. If you get pulled over for a, um...{thinking}.... 'illumination offense' it will certainly be for one of the following:

    (1) Failing to dim your head lights. If you use one of those HID conversion kits that annoy other drivers this is typically the worst that will happen. I rarely see high beam rudeness enforced anymore.
    (2) Head light burnt out.
    (3) Driving with auxillary / off road lights that are distracting for other drivers. Self explanatory.
    (4) Using a monochrome color light reserved for Emergency vehicles; blue, flashing red, etc. Quickest way to get an audition in front of a judge.

    Driving with an XM-L at a couple amps bolted to your bumper is a good way to violate #3. Has nothing to do with color.

    a manufacturer is required to comply with mechanical and light-distribution requirements that are not easy to meet.
    In regards to what may I ask?

  7. #7
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    Default Re: LEDs: Colour temperature from "trichromatic co ordinates"

    Looks like you are looking at illegal uses of a mod for headlights on a vehicle. See Rule 11, last sentence. Thread closed.

    Bill

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