making a small UV-zoomie with the new Ledengin LZ1 360-370nm led

I started this mod a few weeks ago already, but I had to wait for a glass lens from KD to finish it.

In my series let's-try-out-some-leds-from-Mouser the most expensive one at $29 (that is without taxes :-( ) was this newest Ledengin 360-370nm UV-led (partnr. LZ1-30UV00-0000):

It is supposed to put out 1000 mW of radiated UV at only 4 W of power use, that is a very good output and as efficicient as I have not seen yet. The dome is made of glass (that should have been a warning..), and the emitting angle is 70 degrees, which makes this led ideal for a zoomie. I wanted to buy the bare led and fit it somehow on a XML-Sinkpad and do some overdriving it, but with the very different solder pad lay-out, despite some heavy measuring, I realised that it was not going to happen. So I bought it pre-mounted on a aluminium 'miniboard' and decided to stick to the official maximum current.

The driving voltage at 1A (which is the maximum current according to specs, and the current I want to drive it at) is reached at over 4V, so to drive it from a single 14500 size battery it needed a boost driver. I had a spare BLF-mini driver (=a Trustfire mini-01 driver with BLF customised mode spacing and PWM) that is made to boost a cr123 battery of 3V to the led voltage, I figured that it would boost a Li-ion to 4.2V as well. I wired the Ledengin up with the driver and checked the current, and succes, I got 1.03 A on high, just what I wanted:

I wanted to fit it into this SmallSun ZY-A29 AA-zoomie that I modded before with a red XR-E, so this will be its third led:

This host being so small, it has some challenges, the main one being the driver board size: only 14mm, while the BLF-mini driver was 17. I was able to file the driver down to 15mm and let it fload under the pill instead of inside it.

That miniboard appeared to be a rather unusual 11m diameter, so to fit it in the Small Sun that had a hollow pill for 16mm boards, I had to mount it on a piece of copper. The old dutch 1 cent coin is 17mm, and made of solid copper (well, being stiffer than pure copper, it must be an alloy with a few percent other metals I think, but heatsinking should be good enough):

So I sanded the tail-side flat (to show a little respect to our late queen), made two cut-in's for the wires and glued the mini-board on it with ArcticAluminaAdhesive.

Next I glued the board with AAA into the pill:

Now, the driver was not finished with me yet, its components being so close to the edge after reducing the diameter, they shorted to the pill all the time, I resoldered the led wires more to the middle and managed to rip off a solder pad, so I had to move up the minus-wire to somewhere else:

Still I got shorts, so something creative had to be done. I made a few big solder blobs on the minus ring on thebattery side of the driver to make contact with the body and wrapped the driver with Kapton tape to insulate the components from the pill. A last salute to our late queen:

The solder blobs were not high enough to reach the body when the pill was screwed in so I put a piece of wire under in the pill cavity (a piece of a thin key-ring):

Now there was a closed circuit, the led lighted up and all modes worked. And the driver being boost, it also works with LiFePo batteries and even NiMh's (although with less output). As a mule, this light already showed potential, everything bleached (paper) around the light lit up bright blue :-)

But when the lens was screwed on the pill the output decimated, apparently the PMMA the lens is made of does not transmit the 365nm light very well. So a glass lens had to be found, and a 20mm one appeared to be scarse. Finally I found one for 2.5 dollars at Kaidomain, 19.5mm diameter, should fit well enough. So the waiting began.......

.............

.............and after three weeks the lens arrived ( three weeks is ok, could be better, could be worse), left the old plastic lens, right the new glass one:

It is clear that the glass lens has a shorter focal length, actually I like that, it sits closer to the led and catches more light. To actually get it closer to the led, on the front side of the lens an extra o-ring (GITD :-) ) was placed, and on the back side the retaining ring of the led was sanded thinner (no problem, it was huge) to allow the lens to get closer to the pill.

Everything fitted nice and tight now, and yes, and the glass lens worked very nicely with the led, both zoomed out and zoomed in, mod finished :-)


I have get-son-out-of-bed duty early tomorrow morning, so I finish with one action shot of my hobby-mess, light zoomed out. Later I will add a few more. Thanks for reading.


EDIT: more pictures post#11


Thanks for sharing this build. The emitter is kind of expensive :'(

Great build and emitter preview. That beam shot is better than anything I have ever seen in person.

I love aspherical flashlights,

This looks really cool. This could find it's use in forensics or other like false money detection.

I would really like to put that emitter in even bigger aspheric and try on game to see reactions...

It is hard to manage those 18 AWG wires? I tried and found that hard and messy so I stick to 22 awg ones.

Wow, that looks like nice UV output. It better be at $30 for just the emitter. :slight_smile:

I think you’re going the right track, IMO aspherics is better suited than reflector in this application. Focused UV just put more strain to the eye and doesn’t highlight as well.

Light yellow “safety” glasses really should be used with UV. Even the purple portion of the light emitted can be hazardous. Really hasn’t been enough research done for humans but since it kills photoreceptors in animals I wouldn’t risk it. Violet / blue light hazard
Some inexpensive glasses on amazon $3.60 , $4.83 “Safety” glasses use polycarbonate for impact resistance which inherently blocks UV, yellow tint cuts out violet & blues.

I am not a safety hero ( have done my share of careless things in my life) but in my former lab-years we used a uv-lightbox a lot for examining DNAelectroforesis gels (this lightbox needed full face protection), and I learned what the feeling is of high power UV on the retina (not nice!). With this light I try not to look directly into the light and also not too long into the indirect light from the beam. But that is nothing like what I used to feel from the light box. If I will use the light longer than just for a moment, I will use those yellow glasses :-)

I think you are right, the even illumination when zoomed out works very well, the narrow beam zoomed in is a nice bonus but the zoomed out beam is a good enough reason to use a zoomie for this led.

That sounds horrible. :Sp Was it a mistake without the face sheld or even with the sheld? I see people hanging over those boxes, working with their shirts glowing. Is there much violet light in real life? I know cameras can show uv as violet, blue & pink.

Nice work, that turned out really good. I like how you packaged it in a nice small aspheric light.

No, not a mistake, if someone else was watching his gel over the lightbox and I entered the room, you get an instant nasty sting in your eyes, so you was sure to put on the safety glasses immediately. I did however at one point forget the faceshield, had only the glasses on and was severe skintburnt on my face after 1 minute watching my gel. Never forgot the shield again after that :-(

The sun has quite a lot of UV obviously, there is nothing in normal life matching that. Camera's have a lot of trouble with (close to) monochromatic light in general, different intensities are recorded as different colours. Goes wrong with my 400nm light and also with my cyan light.

more pictures, some with mouse-over.

at low (2%) setting

on high, mouse over for zoom-in

the new 5 euro bill, mouse-over for back side

detail

in the woods, mouse over for UV

mouse over for UV

I expected a bit more from the UV-fluorescence in the forest, natural things have not much fluorescence at 365nm really, only weak, so you have to be close with lots of illumination, fungi show white and blue, algae show reddish brown. The light puts out some white-ish light as well, that is why so close-up you see the green as green as well.

LOL, I used the light last night together with my girl-friend to check the kitchen after she did the clean-up (FYI: I did the shopping and the cooking), this light is relentless in showing every grease spot that was not wiped away, a rather sobering sight it was for her, but we had fun doing it .

Keep that up and you wont have to worry about a girlfriend. :wink:

lol, I admit that one should be carefull criticizing your girl’s cleaning skills with the latest Ledengin UV-led while giving a lecture on the marvels of modern technology.
But hey, I got away with tha (but at what costs?.. :wink: )

You will notice a lot more in your forest-walk if you get the yellow lensed glasses. I used the ManaFont UV drop-in to hunt for scorpions where I used to live (https://budgetlightforum.com/t/-/10205) and the yellow glasses made a huge difference. Without the glasses, I missed a lot of the fluorescence. Small things like the fungi that would glow blue/green and then green leaves that fluoresce a dark red were much more noticeable.

Yellow glasses help a lot with 400nm uv-lights because of the very visible purple colour of 400nm. 365 nm light is completely invisible, there is a faint white light coming out of the led as well, but that does not go away with the yellow glasses. I do use the yellow glasses to protect my eyes though..

I see... so the more expensive emitter has a more narrow emission spectrum with a lot less visible blue than my cheap drop-in! Less visible blue is nice, but no way I would spend that much to build a new light for myself. Especially since I've moved and don't have scorpions around any longer. (Cool/Cry)

I am worse: I build lights just because I am curious about them, no scorpions in the city of Amsterdam. It does not even get properly dark here.

Spoken like a true flashaholic!! :smiley: :smiley:

:D


Nice thread djozz!