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Thread: LED Bar - HardHat concept

  1. #1

    Default LED Bar - HardHat concept

    Hi guys,

    While in a holding pattern on flashlight builds, I finally got the motivation together to build out a concept. Actually there are a number of unrelated ideas and elements I wanted to visit and I was able to consolidate a number of them in a single, albeit goofy, conglomeration.

    The ideas and elements to test and evaluate:
    • half round acrylic bar for optic
    • prototype "3 speed" buck converter for Makita Battery
    • viability of an aluminum hardhat as the heat sink for headlamp
    • adjacent mounting of linear array of LED's to minimize multi shadows
    • integration of switch in Makita Dock
    • FLIR evaluation of heat source and its spread in thin and remote sink surface
    • FLIR evaluation of thermally isolated converter












    More details, HERE.

    Now in terms of conclusions, I knew the Makita battery and dock would be ungainly in both weight and exaggerated by its location on the hardhat. Beyond that though, the exercise was quite satisfactory and kind of exciting in terms of some ideas it presents.

    I anticipate that there would be a good market and utility from LED based arrays mounted in hard hats and helmets used in industry as well as transportation. The aluminum is an obvious thermal solution but I would expect other solutions could be found with partial integration of either metal or thermally conductive plastics or laminates in a hat or helmet construction. The electronics and battery supply can either be on board or remote, depending on the application and needs.

    Ultimately though, the key is in the beam and its distribution. On this note, the proverbial beam shot:



    As it turns out, this prototype provided an almost ideal flood of good color rendering light which essentially covers the field of view to the hard hat wearer with little wasted light beyond the field of view. I think there is some real and exciting potential for us modders in using the simple half round acrylic rod stock for optics in head lamps as well as bike and other transportation type head lights. The acrylic is easy to work with and shape and then polish. You can even allow for focal adjustment of the bar in moving it into and away from the linear array of LED's. The Nichia 083's lend themselves well to such an optic because they have no raised dome and you can seat the optic down on top of them. The Osram Dragons without domes are also quite friendly to this. For LED's that do have domes, you may want to go with larger 1/2 round bar to capture and bend more of the light output.

    My only regret in retrospect is not having done this "experiment" prior to building a LED cluster for my Vespa Scooter.
    Build Prices .... some mods and builds (not 4 sale) "Nature can be cruel- but we don't have to be."~ Temple Grandin

  2. #2
    Flashaholic* Carpe Diem's Avatar
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    Default Re: LED Bar - HardHat concept

    Nice concept.

    And who, BTW, is the person modelling the hardhat in the the last picture?

    Proud custodian of Tvodrd`s works of art; Peter`s Arc`s and Brass Arc AAA; Mike Jordan`s gems; some really great lights from Enrique, Fred and Tain ....and *several* of Don`s mods, Ti`s and McLux masterpieces.

  3. #3
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    Default Re: LED Bar - HardHat concept

    Somehow the beamshot has something creepy to it

    Nice idea !

    Now build that into a small lantern-like light and I am all over it. Aluminium helmets aren't so en vogue here in the old world these days

    I can see some flat flashlight with a string of those LEDs next to and not in front of the batteries ...

    bernie


    P.S.: thanx for sharing !!
    There is a type of perfection that transcends the quest for lumens. Buying a $250 1-cell light for "lum factor" is like buying a $250 single malt Scotch for the alcohol content.
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  4. #4

    Default Re: LED Bar - HardHat concept

    Will there be a Ti version?

  5. #5
    Flashaholic* BigHonu's Avatar
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    Default Re: LED Bar - HardHat concept

    NICE!

    How do you switch speeds?

    How big is the array and housing? 2.5 x .75 inches?

    The beam pattern looks to have a decent horizontal cutoff, while retaining good vertical coverage. Might eliminate the need for a wide-angle pivot for the housing.

    That face on the rock still gives me the heebie jeebies!

  6. #6

    Default Re: LED Bar - HardHat concept

    Carpe,
    Low budget self portrait but I figured the silhouette shot wouldn't cause too many lost meals.

    Bernie, yeah, I visualize a deck of cards package with the bar on one edge and pair of cells parallel and behind the bar. Of course a visor clip on one side.

    TB,


    BigHonu,
    I have a couple 3 speed protos from friends in Japan. They cycle through the levels by virtue of a very short off period bracked by on periods of any duration on either side. That is to say you can turn the light on for the briefest of flashes or for hours and it comes on in the last level selected. If you find you are not at the level you want, turn the light off and quickly back on to advance to the next level. The light cycles through low, med and high and then back to low again. The UI is quite simple and straight forward, in my estimation. One of the things that held me back from building this thing was the concern that I should have the bar on a piviot or rotational mount. This adds complexity and reduces the thermal connectivity to the hat. I guessed at what I wanted in terms of down bias and my guess worked out quite well.
    Build Prices .... some mods and builds (not 4 sale) "Nature can be cruel- but we don't have to be."~ Temple Grandin

  7. #7
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    Default Re: LED Bar - HardHat concept

    LOL, I like that rock too that the hat is sitting on, looks like a chubby asian dude!
    -Will-

    Sorry, I have retired from flashlight modding, I do not offer machining services, & I do not make custom flashlights. Thank you for your understanding.

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  8. #8
    Thread Killer Illum's Avatar
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    Default Re: LED Bar - HardHat concept

    Quote Originally Posted by TranquillityBase View Post
    Will there be a Ti version?
    Ti as a heatsink?

  9. #9

    Default Re: LED Bar - HardHat concept

    That module would be kickarse for MTN biking...

    Monster flood for picking out those nasty rocks and roots

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    Flashaholic* FrogmanM's Avatar
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    Buttrock Re: LED Bar - HardHat concept

    Quote Originally Posted by McGizmo View Post
    Carpe,
    Bernie, yeah, I visualize a deck of cards package with the bar on one edge and pair of cells parallel and behind the bar. Of course a visor clip on one side.
    If it's Ti I'm there! MO waiting to be sent McG!

    Mayo

  11. #11
    Flashaholic* BigHonu's Avatar
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    Default Re: LED Bar - HardHat concept

    Don,

    UI sounds straight forward and simple. Perfect for a constant-on application.

    I am really liking the form and implementation of the acrylic bar!

    Since the converter is cylindrical, I'm guessing you start with 1" bar stock and mount it in one end, along with a McClicky. Have the array setup like shown in the middle. At the other end, there is a deep reccess milled in to accomodate a reflector and another LED for some throw.

    The converter can control the array for a low-flood and medium-flood, then kick in the reflectored LED for some throw. Since the array and the single LED are not on at the same time, the tints don't have to match, but just need to be close.

    Just need to figure out where to put the batteries......

  12. #12
    Flashaholic* AndyTiedye's Avatar
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    Default Re: LED Bar - HardHat concept

    I'd like to hook up one of those heads to a gooseneck as a desk lamp.

  13. #13
    Flashaholic* KeyGrip's Avatar
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    Default Re: LED Bar - HardHat concept

    Quote Originally Posted by AndyTiedye View Post
    I'd like to hook up one of those heads to a gooseneck as a desk lamp.
    Amen to that. Indoor lighting applications are endless.
    "Et lux in tenebris lucet"

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    *Flashaholic* precisionworks's Avatar
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    Default Re: LED Bar - HardHat concept

    aluminum hardhat as the heat sink for headlamp
    Now that's what I'm talking about ... no wimpy little quarter sized piece of Al or brass

    I have a Milwaukee V28 battery that needs a nice home ... any way to make a driver that takes 28v & runs the 083's in regulation? Runtimes would be nearly forever
    Surefire® boring including E-Series & Weapon Lights, gun repairs, blueing & custom work * PM's disabled * Please Email & PayPal through Precision-Gunsmithing.com

  15. #15

    Default Re: LED Bar - HardHat concept

    That looks very cool. The beam shot is amazing. Any chance of a bicycle helmet version? A bike helmet could probably have less aluminum because of the wind.

  16. #16
    *Flashaholic* precisionworks's Avatar
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    Default Re: LED Bar - HardHat concept

    Since we're throwing out ideas (which may be worth exactly what they cost ... nothing) it would seem easy enough to integrate a multi-level driver. Make the light bar part of a head lamp, wear the battery on a belt clip, and have color correct, adjustable output ... pretty awesome.
    Surefire® boring including E-Series & Weapon Lights, gun repairs, blueing & custom work * PM's disabled * Please Email & PayPal through Precision-Gunsmithing.com

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    Thread Killer Illum's Avatar
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    Default Re: LED Bar - HardHat concept

    Quote Originally Posted by Art Vandelay View Post
    That looks very cool. The beam shot is amazing. Any chance of a bicycle helmet version? A bike helmet could probably have less aluminum because of the wind.
    greater surface area would be better if cycling though, more area to dissipate heat

    Don, whats the weight on this thing? is it balanced? the battery pack looks awfully heavy

  18. #18
    Flashaholic* starfiretoo's Avatar
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    Lightbulb Re: LED Bar - HardHat concept

    Interesting concepts. How's the balance with the battery pack in the back? Would be a novel way to carry just an extra battery pack.

  19. #19

    Default Re: LED Bar - HardHat concept

    Quote Originally Posted by Illum_the_nation View Post
    .....
    Don, whats the weight on this thing? is it balanced? the battery pack looks awfully heavy
    The whole rig weighs 2 lb & 2 ounces. The battery alone is 13 oz.
    For just walking around, the balance is manageable but I would not want to make quick head movements as the inertia of the battery and its distance from your head give it a chance to wag the dog as it were. If I had a viable 3 speed boost converter, I would have been inclined to have mounted a 2x123 battery pak with tail switch on one side of the hard hat for powering the light bar and a 2x123 flashlight on the other side of the hat for balance and the added benefit of a collimated beam source in addition to the flood. This string of 4 Nichias is akin to a Luxeon 5 watt in terms of power consumption on high.

    As compiled, this hard hat was more of a test bed for a number of items and ideas as opposed to something designed for optimal fit and function. I have no doubts that this thing will see some modifications and changes. I don't know it it is a "Bozo NoNo" to wire two 9V batteries in series but I would think that a bank of 4 or 6ea. 9V batteries wired for 18V out would run the light bar and converter for a reasonable time and the batteries could reside around the perimeter of the hat in some form or fashion.
    Build Prices .... some mods and builds (not 4 sale) "Nature can be cruel- but we don't have to be."~ Temple Grandin

  20. #20
    Thread Killer Illum's Avatar
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    Default Re: LED Bar - HardHat concept

    its a very nice addition to have while your riding on your titanium shovel

    I can see it already, Nichia CRI on all sides of a round hat [the kind German army had back in WWI], modded with a "chasing LED" control board and walking around in the dark with it on.

    "UFO identified in Hawaii"
    Last edited by Illum; 07-17-2008 at 09:58 AM.

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    Flashaholic* Chronos's Avatar
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    Evilgrin07 Re: LED Bar - HardHat concept

    If it could be made waterproof there may be a use in caving and possibly climbing.

    I know I'd LOVE to have that beam pattern and high CRI when hiking at night. Wow.

    Don, any remote chance of you building a high CRI headlamp??? That beam pattern is perfect, the color rendition would help with my aging eyes issues in not being able to identify a 3D object when the LED washes it down to a 2D artifact. Minimize trips and help ID handholds in a more effective manner.

    Maximum output wouldn't have to be the primary driver to a project like this. I see:
    - Floody beam pattern
    - High CRI
    - A couple of useful light levels: a good low to preserve night vision (80+% of use) and a good high when needed (less than 20% of use)
    - Some level of water resistance so it can be used in the rain and snow
    - Perhaps the ability to run off of 2x123 (or maybe a 17670 or 18650) for longer runtimes

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    Flashaholic* KingSmono's Avatar
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    Default Re: LED Bar - HardHat concept

    Very cool concept... I've always thought that a CamelBak system would make a good battery-host for something like this. If the person didn't want to wear a slim battery backpack, then you could use something like the "PackTeen" (pictured below) clipped or fastened somehow... and since you can clip the water-tube to your clothing, it'd be an easy way to run the wires. Just a thought!

    Last edited by KingSmono; 07-17-2008 at 05:46 AM.
    "There are two kinds of light--the glow that illuminates, and the glare that obscures."

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  23. #23

    Default Re: LED Bar - HardHat concept

    I think the front end composed of LED's and optic is really easy and straight forward here. The challenge is in selecting a proper driver and battery source and then how to host these elements either together or remote from each other.
    Build Prices .... some mods and builds (not 4 sale) "Nature can be cruel- but we don't have to be."~ Temple Grandin

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    Flashaholic* AndyTiedye's Avatar
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    Default Re: LED Bar - HardHat concept

    Any idea how much heatsinking it needs besides the aluminum(?) bar the LEDs are epoxied to?
    Would that be enough if we ran them a bit below max current?

  25. #25
    Flashaholic* adamlau's Avatar
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    Default Re: LED Bar - HardHat concept

    Interesting. Not the hat, but the FLIR shots. We use one to evaluate the heat loss and gain of building envelopes. I will grab our FLIR for beamshots sessions the next time around .
    强光手电是我最爱得

  26. #26

    Default Re: LED Bar - HardHat concept

    Quote Originally Posted by AndyTiedye View Post
    Any idea how much heatsinking it needs besides the aluminum(?) bar the LEDs are epoxied to?
    Would that be enough if we ran them a bit below max current?
    Andy,
    If you look at the results I posted, HERE, where there were 6 of the Nichias in the series string, I think you can get an idea of how much sink material is required. I wouldn't expect the light bar on its own to handle more than a single under driven LED let alone 4 of them. What I wish I had a better feel for is how mass of sink relates to surface area in terms of thermal relief.
    Build Prices .... some mods and builds (not 4 sale) "Nature can be cruel- but we don't have to be."~ Temple Grandin

  27. #27
    Flashaholic* AndyTiedye's Avatar
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    Default Re: LED Bar - HardHat concept

    If the current was stated for either of these, I must have overlooked it.

    What current are you running through the hard-hat LED bar?

    I assume that's a 350ma Xitanium in the other post with the 6 LEDs.

    Are these LEDs more efficient at lower current levels?

    A stand-alone light bar could also have slots cut in the back of it to improve heatsinking,
    the way people often do with modded Maglites.

  28. #28

    Default Re: LED Bar - HardHat concept

    Andy,
    On this LED bar here, high is ~330mA with med at 115 mA and low at 27 mA. In the example of 6 on a Xitanium, I measured 360 mA to the string on that particular driver (nominal 350 mA device). This lot of Nichia 083's does have a high Vf unfortunately and this means more heat and less photons than we are now used to with the current high power LED's.

    Yes, you could cut fins in the LED bar which would increase surface area at the expense of mass reduction. Presumably this would have a net gain in thermal relief but to what extent and if there is some limit at which reduction of mass itself works against you, I don't know.
    Build Prices .... some mods and builds (not 4 sale) "Nature can be cruel- but we don't have to be."~ Temple Grandin

  29. #29

    Default Re: LED Bar - HardHat concept

    Lots of mass in a heatsink only helps until it's hot, then it becomes a question of how fast heat leaves the heatsink which is a function of surface area, surface finish, and the heatsink shape. You do need sufficient material thickness to get heat conducted to the outer areas of the heatsink, so yes, past a certain point reducing mass will reduce the effectiveness of your heatsink. And for short and intermittent use, a heatsink with high mass and low surface area, or poor geometry, etc., could work OK assuming it would cool between uses.

    Now that you have FLIR you can answer a lot of questions about what does and does not work, it looks like the hardhat is a pretty good heatsink. Maybe a bit of a bottleneck getting heat from the brim to the crown.

    It is amazing what difference a finish can make too. I remember an exercise from college thermodynamics o-so-many years ago: Which gets hotter in the sun, a chrome plated steel plate or a black painted one? It turns out to be chrome, even though it reflects most of the light hitting it, it re-radiates very little of what it does absorb and ultimately will settle at a higher temperature than the black plate.

    Back on topic, I suspect that increasing the contact area between the bottom of the LED bar and the hat brim, and/or putting a plate on the brim to help transfer more heat to the rest of the hat will result in more heat loss than fins on the top of the LED bar would.

  30. #30

    Default Re: LED Bar - HardHat concept

    Mahoney,
    Thanks for the comments. Since I have been messing with the FLIR, I have been introduced to the concept of emissivity. If I don't calibrate the FLIR camera for the emissivity of the object being viewed, the measured temps will be off. I assume that the emissivity of a surface also has bearing on the object's ability to radiate heat.
    Build Prices .... some mods and builds (not 4 sale) "Nature can be cruel- but we don't have to be."~ Temple Grandin

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