Would like to modify flashlight for 3W 365nm UV LED on 20mm star

I'm thinking of making a birthday present for my cousin. I have a 365nm 3-4W UV LED on a star, hooked up to a current regulator (that I bought long ago from unknown source), and 4-AA battery pack. It's just hacked together for testing, but my cousin, who is studying geology thought it was fantastic. (the UV makes certain minerals (rocks) fluoresce, which means something to him (to me, it's just kind of neat))


So what I'd like to do, is find a flashlight that's easy to disassemble, has a 20mm LED star on it and current regulator ALREADY, pop it apart, throw in the UV LED, and give it to him.


Any advice on where to find something like that? I have an old Pelican M3 LED flashlight that I've taken apart, put newer LED's (on star) in it from time to time, but it's well used, and I don't really want to give him that. Also, it takes CR-123 batteries, which are expensive to run. AA's would probably be best, but, I'm flexible, if it needs to be lithium batteries, I can get him some rechargeable ones & a charger.


I will probably use an LED like this (ebay link), the optics really don't matter. (this is what I hacked together that he thought was super cool)


https://www.ebay.com/itm/3W-365nm-U...h=item2877bdf478:g:WI8AAOSwIkNcPOTE:rk:1:pf:0


If I'm in the wrong forum, or there's info already out there, feel free to kick this post wherever is needs to go. I didn't really see anything like I was looking for in the forum, but there's a lot of stuff here.


Thanks in advance,
B

Convoy C8 host and 17mm 7135 based driver bought on Mountain Electronics and you should be set

Ok, I'm looking into that. Had the wrong Mountain Electronics at first.

The LED I'm thinking I'm going to use has a ~3.9v forward voltage, if I use one 18650 battery, wouldn't that be too low of a voltage?

I'm not married to my LED choice, if there's something out there that's better, or easier to use. I like the one I have because I know it doesn't put out much visible light, compared to a 395nm UV LED, and does put out a lot in the true-UV spectrum. That's really an important aspect of this project, your regular 5mm LED 'pet stain finder' flashlight at 395 or 405-415nm has WAY too much visible light.

FWIW, plastic lenses or covers over the output of the LED are a no-go, they absorb too much UV light.

I wouldn't mind trying a 245-265nm LED (as a different project/test) but I can only find ones (that are affordable) that max out at .12mW or so.

Also, I found 365nm flashlights for sale from various places, I don't know if they're any good or not. I'll order one & see.

Thanks for your help!

PS - so many driver choices! I had no idea such things existed! With 22 different modes and different firmware - crazy!

If anyone is interested perhaps in a UV flashlight, I decided to tempt fate & get try ordering one without having tried it first. I ordered a Convoy S2, with 365nm LED from BangGood. It took quite a while to get here, but it showed up a week after my cousin's birthday, that worked out ok. The UV light is pretty good, it's strong, with a metal reflector & glass 'lens' (just flat glass on the end). It takes a 18650 battery (one). Not very much visible light, so it's pretty good for looking for fluorescent minerals.

Probably as good as anything I was going to make for him, with the LED I initially was experimenting with. I had ordered some UV-pass/visible-block filters, but I don't think that he'll use them on this flashlight, because it doesn't have too much visible light anyway. (there is some, for sure, but not like the cheapo 395/415nm lights with 5mm LEDs in them)

I also ordered a cheaper one from some other place, also advertised as 365nm. (had a choice of uv leds - 365 or 395, so 365 is better for his purposes) Haven't gotten it yet, over a month later, so, who knows.

Anyway, maybe if someone comes out with a shorter wavelength, high powered UV LED in the future, I'll try making one of those, but right now the technology apparently is either too expensive or not feasible to use LEDs for around 245nm wavelengths.

He is going to look for minerals and diamonds (hah) and whatnot in 'pegmatites' at night- if anyone is into geology they'll know what that means.

Thanks for your help anyway! I might tackle it in the future, but I got what I needed pre-assembled and everything.

Glad to hear that the Convoy S2 turned out well. How is the beam pattern?

I have an Ultrafire WF-501B with a 365nm drop-in which produces some purplish-white visible light, so I replaced the regular lens with a UV-pass dichroic filter. It blocks visible light well and only produces a slight attenuation at UV. My only complaint is that the beam has a splotchy pattern with or without the filter.

I have a couple of 249nm UVC LEDs on stars and I hope to fit one of those into a flashlight soon. The output is on the weak side but it will flouresce some minerals that 365nm won't. You just need to use it in much dimmer light.

Yes I collect fluorescent minerals.

Beam pattern... I didn't notice splotchy areas, seemed pretty decent. It was obviously a lot better beam pattern than my test LED (see pic) - which I hooked up to a 750ma current regulator I had floating around, and a battery pack. My cousin thought that my little test thing was great, except it wasn't like a flashlight package. He wanted to make a flashlight one, but I had already ordered the Convoy a month or so ago. "Sure, after spring break, I'll help you make one..." Finally arrived.

It has a metal reflector, which is cool, because my test pack didn't have any optics at all. I only had polycarbonate optics for regular visible LEDs, and you put plastic in front of the UV led.. not good.

He was pleased with the fairly minimal visible light, but I did get him some UV pass filters that would fit the flashlight, also. I guess we'll see how it goes. Using it on certain things you could tell there is still a decent amount of visible light, and depending on what you shined it at, might or might not matter. On things that weakly fluoresce, the visible light filter is a good thing. Even though it does attenuate the UV light that is supposed to pass, to some degree. (maybe cheap filter, I don't know) I have a couple rocks that it did make a difference with.

The 275ish-nm LEDs I got that I could afford require at most 20ma. Should have read the product description a little more, eh? Even with the high forward voltage around 5.7-7v, that's only using .12 watts, and probably producing much less.


Next time he's down at my house I'll have him bring it & I'll take a beam shot photo & link to it somehow. It's a much tighter beam than my bare LED with no external optics. More 'throw' as they say.

Thanks for the information Squib. This sounds promising.

The beam pattern on mine is an ugly "E" shaped beam, which represents the die radiation pattern more or less. I will be looking into the Convoy.

Weird. I think that Gearbest had that same UV Convoy on sale for $20..lemme check.. Yeah, I paid $36 or $37 for his, and then after I bought it, they put it on sale for $21. (Grr!) That deal says it's good for the next 5 hours? Or the next 1 day and 5 hours?

Not advertising for anybody, but I wish I saved $15 - here's a link - https://www.gearbest.com/goods/pp_009572644559.html

I don't know how easy or hard it'd be to undo the led and circuitry to get at the glass 'lens' & put in a visible light filter. I didn't want to get it & modify it for my cousin & mess it up before he even got to use it... But if the visible light filter seems like a good idea, maybe he'll be feeling experimental & let me at it. You could also just tape the VL filter over the glass, I guess.

I think fluorescent minerals are neat and everything, but I've got my own UV led thing, otherwise I'd buy one for myself. And wait a month to get it, but that's how it goes. Mostly I like to make things that are neat. Maybe next I'll hack a UV toothbrush sterilizer with a shortwave UV pass filter in front of it, get the shortwave action.

So my cousin brought the flashlight I got him down this weekend, the and a chunk of what I would just say is 'a rock' - the convoy 365nm flashlight did a really cool job of lighting up a bunch of rubies in the rock. They glow bright red, which is pretty cool to me. I've got lots of uranium samples from my grandpa, and they glow green, which is kind of neat, but I've seen that trick. (I've got some uranium glass, etc, also)

He didn't bother to mess with the visible light filter I got for him at the same time, so I think that's pretty cool. There's some visible light, but not enough to drown out the red glowing rubies.

The UV led I mentioned in my first post that I got from ebay _would_ show the rubies as red, but since there's not optics or reflector on it, you had to get it really close, and use a visible light filter. More or less the same story with the $11 UV 365nm light I (finally) got.

FWIW!

Hi Squibb, the S2+ light has a Nichia UV LED which has a solid reputation for 365nm perofrmance and for putting out little visible light. You got a well rated good value UV light in the Convoy.

BTW, a belated welcome to CPF.

Thanks, I've lurked around since forever

I'm going to go ahead and get one of those flashlights, also. My mom talked me into it.. 'you should get a good one like you gave your cousin'. Alright...

I've got a LOT of inherited rocks (and minerals? My cousin often says I call the rocks/minerals/rock-oids/mineroids whatever by the wrong name) of various sorts from various places, as my grandfather was into geology. (Actually prospected Uranium back in the 50's...I've got an old 50's 'Lucky Strike' geiger detector I fixed up from him, also. It's retro-cool (and works!) )

Tell ya what, though, you do not want to go into your bathroom with the nice Nicha UV LED unless you are definitely not a germophobe