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LEDs washed out by sunlight

Discussion in 'Misc Electronics' started by [email protected], Jul 28, 2006.

  1. Guest

    Can anyone point me towards a passive front panel indicator?

    I once saw a tiny flip dot device which moved a yellow disk up behind a

    window. The more ambient light the better.


    What alternatives do I have for my current panel mounted LEDs?


    Any ideas?


    Cheers


    Mark
     
  2. default

    default Guest

    Good luck to you - those things are very scarce these days - and
    weren't that plentiful any days. You might build it with relay
    armatures to set the flags - or kluge something like the motor driven
    trunk actuators they use to replace solenoids.

    I'm using some high efficiency LEDs on my motorcycle tach and
    voltmeter. They are both easily visible and in the case of the tach,
    my point of view is well off axis. Leds are mounted to a piece of
    black painted aluminum and enclosed in a clear ABS plastic dome.

    The LEDs are rated at 20 ma and 3,000 mcd, 15 degree viewing angle. I
    put a switch on them so they could be used at night pulling 6
    milliamps and found that 6 was more than enough in bright sunlight.

    The voltmeter was built some time ago and I do have to have it aimed
    at my eyes to see the condition of the LEDs.
     
  3. John

    John Guest

    Have you tried high intensity LED's?
    Maybe some 18,000mcd white or 10,000mcd red ones from
    www.ledshoppe.com
     
  4. 10,000 mcd green and orange ones are available enough, and blue ones of
    3,000-5,000 mcd are available and more noticeable than their photometric
    numbers make them sound.

    A 5 mm circle of white surface illuminated by noontime sunlight in June
    on top of Mt. Everest is about 9000-9800 mcd. That makes me think that
    really bright LEDs of most colors can make themselves seen anywhere.
    If you need a can't-fail-to-see LED, any lambertian radiation pattern
    type Lumileds "Luxeon" of any color at 350 mA produces a few thousand to
    about 15 thousand mcd from an aparent source size of a 1.6 mm square and
    it is not as directional as most "bullet style" LEDs. And ones of same
    light source size are available with higher current capabilities.

    How about a blinking LED - use a 555 to blink a low power LED, or a 555
    driving a MOSFET or a transistor to drive a high power one? For that
    matter, a blinking Luxeon should be visible at noon in June on Mt.
    Everest with max. output current of a "regular" 555 (100-200 mA) or the
    not much lower max. sink current of TLC555 and LMC555 (low current
    consumption ones with limited source current capability).

    But for something more "passive" as in not needing to outshine sunlight
    - how about something based on LCDs? The mechanical indicators suggested
    by another poster? How about a miniature size meter movement illuminated
    by a very ordinary LED to keep the meter movement visible in the dark?

    How about an audible indicator? (May have to get a bit loud on a
    motorcycle however).

    - Don Klipstein ()
     
  5. Marky C

    Marky C Guest

    Whilst the torch fetish side of me likes the idea of fitting a whopping
    big luxeon, I will have to have a play with using filters, such as
    Neil's idea of using a polarised filter to improve contrast.

    I have however found the following mechanical flip ball indicators

    http://www.l-3com.com/EDI/ball-bis.htm

    These two options comically only answer my problem for 12 hours of the
    day. The bright LEDs will have to be auto dimmed at night, whilst the
    flip balls will have to be illuminated at night.

    I think I will try and fnange a sample of the flip balls.

    Thanks for the replies

    Marky C
     
  6. The yellow and green for intensity setting and the blue gun
    separate, as it has for the millions of years beforehand There
    will be a 3 phase motor. It is a bit better then a belt with a
    wire, i need an actual collar because i also want to get 20V or
    even higher AC voltage.

    Is it compulsory at school to be a disabled veteran? Another
    aspect of your government looking out for your safety.
     
  7. default

    default Guest

    Duh? Are you posting to the "LEDs washed out by sunlight" topic?
     
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