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Thread: reliable homemade flashlight...consists of...

  1. #1
    Enlightened
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    Default reliable homemade flashlight...consists of...

    Hi

    We all know, that if you wont a realiable - top noch flashlight you get yourself HDS, OVEREADY, SF, .....flashlight,
    but what we (at least I) don`t know, is what are real details (components), that makes that flashlights so unique and so reliable.

    So my question would be: which things should be considered when making homemade flashlight, and which components should be
    installed that the light quality would be as high as possible?

    If we star at housing I think we all agree that TITANIUM is the best wey to go, but ALU 7075 T6 also isn`t so bad...
    the most important is that the case is sufficiently robust to protect the electronic components, and that it has good heat dissipation ability.

    But when we come to electronics the things become more complicated....which driver to choose (DW, Taskled,....), and how to install it properly,
    should the electronics be potted, which switch to choose,....and so on...

    So .... what do you think realy makes the flashlight high end and reliable?

    I'm looking forward to your responses...GREETING

  2. #2
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    Default Re: reliable homemade flashlight...consists of...

    No driver, just LED, the best switch you can afford, electrical contact cleaner on all contacts, and lithium primary batteries. Make sure the whole thing is sealed to the environment. That is reliable. Anything else is a tradeoff.

  3. #3
    Flashaholic* AnAppleSnail's Avatar
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    Default Re: reliable homemade flashlight...consists of...

    I'd say:

    LED behind thick optic or window, securely held in place. O-ring in front of, behind, and around the glass, with a durable bezel screwed down over.

    LED securely held against metal of light with good thermal path.

    Anodized aluminum, anodized threads, long overlap and two or more O-rings on each body joint.

    Twisty switch or electronic clicky (MOSfet) for extreme reliability.

    Low power, no modes. A typical XP-G has an excellent Vf for protecting the battery. XM-Ls run Li-Ions down too low.

    Excellent battery quality, primary or rechargeable.

    Sized with battery spacers for variable-cell use.

    Body extenders to take up to 3xD cells. (I suggest a minimum 35mm body, with 35mm, 32mm extender to use 1x18650, and another 130mm extender for 3xD or 3xAA with spacers. All with the O-rings and thread schedule above.

    Keep it lubricated appropriately and never use the wrong batteries. Now do it all again, but precisely and simply. Will it fail? Sure, but a bird will wear down a mountain with its beak first.

    Here is HDS writing about developing his Action Light, a very reliable headlamp.
    My biggest light-hog is my camera.

  4. #4
    *Flashaholic* Gunner12's Avatar
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    Default Re: reliable homemade flashlight...consists of...

    Make the light a direct drive twistie with a separate electrical path. as in, don't use the flashlight's body as a conductor, have a inner layer inside the battery tube as the conductor, kinda like a piston drive. Fill everything besides the battery tube with epoxy (including inside the reflector, optical grade epoxy). Maybe add a glass at the front for scratch resistance, and a gasket that fits around the edge of the glass. Dual O-ring for the battery tube.

    To avoid water ingress from the twistie, a reed switch could be used with a magnet on the outside. Perhaps even a two stage body, thinner OD threads on the inside, dual O-rings, another layer of thicker OD thread, and another dual O-ring, maybe even a gasket at the step between the different thread ODs. Of course, make sure the body is nice and thick.

    No driver to burn out, flooding the battery tube would just kill the battery, no little switch components to wear out. Only two metal parts for the light (three if using a Reed switch, the third is the piece that holds the magnet), and thick walls to protect against crushing.

    For something a bit more practical, a driver can be used, but make sure that there are backup drivers in case one fails. Or a QTC foam, so it has adjustable output without a driver.

    Overkill, yes. Durable, most likely (haven't built one, so I don't know).
    Last edited by Gunner12; 09-14-2012 at 02:37 PM.

  5. #5
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    Default Re: reliable homemade flashlight...consists of...

    Nice responses.....exactly what I wanted

    So it is important that things are as simple as thay can be, and that flashlight includes only essential components.

    and I already have some questions:

    - what is the benefit of potting the electronics and which thing should be used for potting?
    - why a flashlight body should not be used as a conductor?


    this thread about HDS developing the Action light is also very interesting....

  6. #6
    *Flashaholic* Gunner12's Avatar
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    Default Re: reliable homemade flashlight...consists of...

    If the light is meant to be used underwater and the body is used as a conductor, then the electricity can escape the light and drain elsewhere instead of powering the light. The electronics should be potted to prevent mechanical shock from breaking the electronics. I've broken an inductor abusing a light before, if the light was potted, that would be less likely to happen.

  7. #7
    Flashaholic*
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    Default Re: reliable homemade flashlight...consists of...

    Plus potting can increase heat transfer from driver components to body and prevent moisture ingress. There are many (expensive) potting compounds available or you can do it the DIY way and mix aluminium oxide into epoxy resin.
    I cannot pretend to feel impartial about tint colours. I rejoice with the brilliant ones and am genuinely sorry for the poor browns.
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