6 volt DC. LED FLASHING BEACON

Discussion in 'The Projects Forum' started by Tkaeding, Oct 24, 2013.

  1. Tkaeding

    Thread Starter New Member

    Oct 24, 2013
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    Hello all,
    I and building a 6 V DC portable LED beacon. I would like to power it with 4D cells in series or 2D cells in series for 3 V. This Beacon will be used one hour and then put away for a day and then used another hour put away for a day. My primary focus is brightness. 100° viewing angle would be more than adequate. I can have one vertical LED and one the horizontal horizontal LED. Any help advice would be super appreciate it. Thank you. Tom
     
  2. wayneh

    Expert

    Sep 9, 2010
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    Is there a reason you are building one instead of choosing from the many already available?
     
  3. mcgyvr

    AAC Fanatic!

    Oct 15, 2009
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    I'm always amazed how 3rd world countries can't get stuff like an off the shelf LED beacon but yet can easily get the IC's/Components,etc.. to build one from scratch..
     
  4. Tkaeding

    Thread Starter New Member

    Oct 24, 2013
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    All research has shown very low intensity LEDs. Battery life is always the driving force it seems. My primary goal is long range visibility in the open ocean.
     
  5. Tkaeding

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    Oct 24, 2013
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    #3
    Today, 12:07 PM
    mcgyvr
    Senior Member

    Join Date: Oct 2009
    Location: North Carolina, USA
    Posts: 2,280

    I'm always amazed how 3rd world countries can't get stuff like an off the shelf LED beacon but yet can easily get the IC's/Components,etc.. to build one from scratch..

    It's going to be a process, but I'm slowly working through it. Your right about the supply chain in Asia. I tried an Asian beacon and the issue was massive power consumption and a large bulky form factor that was not waterproof. I need a simple simple design
     
  6. wayneh

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    Sep 9, 2010
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    OK, so that means white light with a horizontal dispersion up to 100° with relatively little vertical dispersion required.

    How much light do you want? I mean, can you define the watts or lumens that you want? Please also define what you mean by "flashing", in terms of frequency and duty cycle. Do you want it to rotate, or just flash?
     
  7. Tkaeding

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    Oct 24, 2013
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    Just flash will be fine and I believe Limens will be limited by the 9 volt supply I would like to use 4-6 nine volts in parallel.
     
  8. Tkaeding

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    Oct 24, 2013
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    100 flashes per min. So it's different than anything on the ocean
     
  9. Bernard

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    LED color? With one horizontal LED, how do you keep it pointing in desired direction? What range? How high above water?
     
  10. wayneh

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    I'm wondering if there are maritime regulations regarding such things.

    And I still don't understand what's wrong with the MANY commercial options:
    Vega
    Edwards
    Pharos
    MSM

    These all look nicely engineered and purpose built. I think it's a little bit of hubris to think a DIY will be better.
     
    Last edited: Oct 24, 2013
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  11. Tkaeding

    Thread Starter New Member

    Oct 24, 2013
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    LED color? With one horizontal LED, how do you keep it pointing in desired direction? What range? How high above water?

    Color : red
    It's mounted in clear, sealed lexan tube.
    The light mounts to a 10" collar that has ballast at its base. I have tested it and the dummy light mounted at 18" above water level remained vertical in 6' seas
     
  12. Tkaeding

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    Oct 24, 2013
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    These all look nicely engineered and purpose built. I think it's a little bit of hubris to think a DIY will be better.

    #1. None of the Beacons have a true vertical projection LED.
    #2 my form factor for the specific project is very important non of these represent weight and physical characteristics of what I need.
    #3 Quite a bit of engineering and testing has gone into my enclosure. It's one that fits my purposes exactly. The enclosure is very specific.
     
  13. wayneh

    Expert

    Sep 9, 2010
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    Ah well, it would have been helpful to learn these details earlier.

    So do you envision a single red LED, or perhaps a strip of several? Since you want red, you might look at automotive LED tails lights, or something like this.

    Brightness trades off with battery capacity and length of service. So far you haven't specified any of those 3 requirements. I recommend against the 9V batteries because of their low capacity.

    The flashing part will be easy once the power supply and LED are identified. You'll use a 555 timer circuit driving a MOSFET switch. Depending on what you need, you can have control over both frequency and duty cycle.
     
  14. Bernard

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    Aug 7, 2008
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    I just tried out a flashing { 100 ms on 900 ms off ] red piranah LED, 120 deg, 66mA, 2.5V, in full sun at 300ft & still visable. Battery 3 AA Ni-MH 2400 mAhr, so should last for 140 h. AA alk have about same Ah but V drops quickly under load. If I were stuck with alk. a small boost-buck board would hold V constant, but would still need 3 to keep 3 V at near end of life. Looks like a Cree CP42B-RKS-CLOPOAA4 is about the same as the one I used. LED is still visable for full 180 deg
     
    Last edited: Oct 25, 2013
  15. Tkaeding

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    Oct 24, 2013
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    Bernard, thank you for the advice. I cut and paste the Cree LED that you recommended but was unable to find it on Crees website. 180 degrees of visibility would be awesome.
     
  16. wayneh

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    Is the high side switch chosen because the 555 output pulls low better than it pulls high? In other words, why not the usual low side switch?
     
  17. Bernard

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    wayneh, right on, would like about 14 mA base current which pushes C555 high output.
    Digi-Key SN: CP42B-RKS-CLOPOAA4-ND, $.20; also Mouser & others.
     
    Last edited: Oct 26, 2013
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