Water-cooled 72,000 lumen LED flashlight


Originally published at: http://boingboing.net/2017/03/31/the-dazzler.html


This is a rare case where the YouTube comments are quality, so I will just recommend everyone go there for a good chuckle.


So is staring at that with your naked eyes from a meter or so away better or worse than staring at the sun? Wikipedia says sunlight is 98,000 lumens per square meter. I imagine the wavelengths emitted would be a factor as well.


That is a good project, and a well photographed and narrated video. As a flashlight fetishist, I approve. Of course, now I have to top it. Of course, I would want to build it in IR, instead of visible spectrum. For use with night vision scopes.


You might have to immerse the entire IR output stage in electrically non-conducting fluid to keep it from melting. And wear oven mitts. :wink:


…or as a flame cannon?


Can you still call it off-roading if you burn/melt your own road as you go?


I am already having lots of fun with IR lasers. My son is puzzled that we have not built a flame thrower, so a flame cannon would not be out of the realm of possibility. But back on topic, this is a very nice project, and I am thinking of applications. I was actually thinking of a fixed IR light, triggered by motion sensors, as our perimeter cameras use IR. We have IR floods, but this is a different ballgame. If they make emitters in IR, or full spectrum that could be filtered, but still provide enough IR to be worth the trouble.
But it is an inspiring post, and worth investigating.


IR would actually be (modestly) easier to cool, for an equivalent level of output. The phosphor layer in white LEDs both does their efficiency no good; and has a bad habit of degrading, especially if overheated. Since IR(or any other mostly-monochromatic LED option) skip that step, you get better efficiency and lifespan, at obvious costs to color rendering.

Speaking of efficiency, though, was anyone else struck by the fact that somebody using LEDs of this magnitude(and price) appeared to be using Ye Olde ‘just put a current-limiting resistor in series and call it a day’ LED drive circuit?

For teeny little indicator lights and such, the tepid efficiency hardly matters; and the simplicity is hard to beat; but this is a situation where losses are not going to be able to fit under the rug labelled ‘negligible’ and used to store our technology’s dark secrets.


If I could go back in time and blow Thomas Edison’s mind…


I too came here to say that it’s absurd that he’s using current limiting resistors and wasting at least 20% (if not more) of his energy and similarly not able to have his light deal with temperature or voltage variations rather than just using a standard off the shelf current limiting power supply.


Ok, it’s a long way from being in the same league, but I realised the other day that you can pick up LED replacement bulbs for those big Maglites for cheap (~£15) nowadays.
For years my big maglite has sat by my bed, more useful as a club than a torch. But now, now it has the brightness to go with it’s heft! I’m going to enjoy dazzling people with this :slight_smile:
(plug ‘maglite LED replacement bulb’ into your favourite search engine)


No need for more power that’s bright enough!


You’ll have to top the 2.1kw one built by “PhotonicInduction”, as well…

Sorry, but if I saw a big maglite by someone’s bed, ‘a club’ is not what I’d assume it was used for.

(I still use a maglite with incandescent bulbs for newt surveys- LED torches just don’t penetrate cloudy water as well as incandescent, for some reason).


My drunkard-startling lamp was also good tonic against the opsec-challenged drug-dealer who’d park his boom-car under our window at 3AM and wait for his subcontractors to bring him the night’s take

I’m not sure this was a good idea. After all they would know exactly where you lived, and if they wanted to make an example out of you they could. I had a friend who did something similar with some drug dealer on their street and they ended up bashing the windows in his work truck. They moved after that. Just call the damn cops.


Well, duh.

It’s obviously for use as a reading lamp.


opsec-challenged drug-dealer who’d park his boom-car under our window at 3AM and wait for his subcontractors to bring him the night’s take; a high-lumen reminder that he was advertising his presence to people who could narc him out with impunity

Speaking of opsec, the drug dealer can park his car anywhere; you can only live in the apartment that you’ve drawn his attention to with your giant flashlight. That’s not the kind of impunity I’d recommend where drug dealers are concerned. If he responded to your light, it was probably more out of politeness than any concern that the cops would learn anything about him that they didn’t already know.


This upgrade also frees you from having to master the old cop skill of remembering which end is for blinding and which end is for pain compliance and rotating the flashlight accordingly. A decent LED module is vastly more shock resistant.


A quick look at Ebay suggests that the “cheap 'n monstrous emitter array of unknown provenance; but did I mention cheap?” sort of LEDs are slightly less common in IR than in white, presumably because demand for IR is somewhat smaller than demand for LED lights(the opposite is true for small LEDs, which are a fiddly way to get good looking illumination; but have obvious applications as indicator lights and for IR data transmission); but the “giant, nominally 50W array”, “3-5w Luxeon/LimiLEDs-alike”, and ‘zillion different arrays of discrete SMTs or 5mm through-holes’ segments all seem to be covered.

(edit: if you actually want the result to be reliable over time; you might want to splurge on a real vendor; some cheap LEDs really do their best to live up to their price; but when it comes to hacking something together for your amusement, the (initial) brightness per dollar is pretty impressive; and sometimes even lasts a while.)

You could definitely give any IR sensitive cameras you have quite a show.


After you get burns on your retinas it kind of stops being a “that one is worse” kind of thing.