Infra red led for cctv

Discussion in 'The Projects Forum' started by kevmac72, Mar 12, 2007.

  1. kevmac72

    Thread Starter New Member

    Mar 12, 2007
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    I am trying to find a really bright infra red led. It needs to be arround the 950nm spectrum so it is invisible to the human eye. I need to provide illumination for a black and white ir sensitive camera. It only needs to illuminate a distance of about 1 metre and powered from a 12v dc source. I can only use 1 led. I have tried a few from Maplins electronics with what i think is the right resistor, but i only get a very dull glow. Nowhere near enough to illuminate anything from 1 metre.
    I have tested the camera using the light from a domestic IR remote control which nearly gives enough light.
    Can anyone suggest a 3mm or 5mm ir led and the correct resistor ?
    the camera specs don`t give me the iR frequency response but it does react to a domestic ir reote control.
     
  2. thingmaker3

    Retired Moderator

    May 16, 2005
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  3. Doktor Jon

    New Member

    Jan 22, 2008
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    I realise this is rather an old thread, but just to mention, the spectral response for most monochrome camera CCD imagers is generally rather poor above about 850nM, so by the time you get to 950nM, the response may only be 5 - 10% (unless it's a high end camera, where the response can be more around the 40+%).

    This means that in order to exploit a high IR frequency, you need to substantially increase the amount of light being emitted.

    So whilst a remote controller might be emitting a relatively low output at perhaps 820 ish nM, the camera will actually see it is a bright light source. If you tried the same test again with a 950nM LED, it would look very dull.

    Bottom line is, with most B/W cameras in general, the higher the IR frequency being used the more light will be required to produce a usable image.
     
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