Except that the optic does not have optimal UV-transmittance. I have no numbers but it is at least a lot worse than glass. If you loose 40% (I make this number up) because of crappy transmittance of the optic you loose the advantage of good leds.
If I would have a C8-size UV filter, I would make Sofirn C8F with these leds.
^
Hence the swap I mentioned. Good idea to mention that though. I was just thinking the 3 emitters alone for under $14 is a good deal. Plus you get a nice triple MCPCB and optic for other projects.
I can feel a triple UV emitter build coming on 
I’m trying my luck at alibaba atm for 20 pieces of 40mmx2mm ZWB2 filters. Will get a quote on monday, could be affordable or not, no idea…
Amazing work and invaluable info. You have done it again djozz. Thanks. 
Thanks Steve, I’m not sure about the ‘invaluable’ though, UV led use is a pretty obscure corner of an already obscure hobby. Without these tests, I’m sure the world would keep spinning as usual.
Already got the quote in for 20 pieces of 2mmx40mm ZWB2 filter (fitting the C8), And I’m a bit double about it. They cost $9.50 each, with 50 dollar shipping. So that is an investment of $240 dollar which is not nice (I hoped for under 100).
On the other hand, if I could buy them for 12 dollar plus shipping (which is just $1.80 from my place to worldwide), I would buy 2 of them without hesitation.
So if I know beforehand that I would sell 17 of the 20 pieces, I would do it, but I doubt that there’s interest for 17 ?
Edit: I started an interest list:
I will take two djozz.
Just to be sure about my reading skills. At this moment a black C8 with an LD1-driver with no modes (eh, 1 mode) is useless lying in a corner. Do you mean that without risk I can put in an LG UV-led from Simon?
Yes, you read it correct, provided that it is mounted on a DTP-board it will run in any direct drive situation with a single li-ion, so the LD1 should be fine. With the disclaimer of course that I do no testing on the lifetime of leds when driving them out of specifications.
Thanks
Edit (almost one week later): Well, that UV-led is on it’s way. Can’t wait to team it up with one of your ZWB2 filters.
I hope for an obscure but interesting new type of light: the UV-thrower.
Btw, the ordered filters should be underway by DHL at this moment, tracking says underway from Le Havre to Netherlands.
Could anyone give me some driver ideas for a 3x SeoulViosys build?
I have simply no experience with UV lights, djozz’s filter was kind of an entrée. Now I sit on 3 LEDs from Kaidomain and a very nice Sofirn C8F host and try to figure which driver to build.
- mA
The spec for the SeoulViosys says 500mA but djozz’s test show they can cope with much more. But I’m not eager to use a FET/DD driver with this LEDs. Thinking more of a 7135 linear driver in the 2100-3500mA range at the moment. Too conservative or overkill already?
- modes
Are any modes useful or just single-mode? Or just no moon-mode? What about ramping, would you even properly see when you’re at low or high?
As I’m always ready to design a new oshpark driver from scratch for a certain light, I could very well make a, say, 17mm/9x7135/Attiny85 driver to get 3150mA and the latest fancy firmware. Any ideas?
Thanks
HQ
I tend to want a simple user interface for a UV light, I have one with low-med-high (no memory) and I like it.
I plan to make the same light as you (C8F+SeoulViosys leds) and I think I will use a LD2 driver (I still have one in my spare driver box, but l4p does not have it for sale anymore) so that 2A per led which sounds quite optimal to me.
Here is my build with the C8F and three SST-10s UV triple using Sofirn C8F . I decided on using these after djozz tested them but before he tested the SeoulViosys leds. Oh well, live and learn. I just used the stock C8F driver from Sofirn. It has multiple modes that really aren’t needed but since I am a newby it was an easy choice that I knew would work. Lexel has pointed out in this thread the limitation of a single 18650 which will keep the leds from being overdriven. I really like it. I am interested to try the ZWB2 filter from djozz versus the ZWB3 that I made and put in mine initally. I don’t think there will be much difference.
Thanks for the input, guys, really appreciated. Hadn’t seen your thread, Scientist, I like the glass cutting part. :nerd_face:
So less modes then.
I think I still have a 5A LD-1 lying somewhere, although I never rigged one for momentary use. I’m much more confident when the driver limits the current, so I don’t have to worry which cell I use. A 25R can deliver lots of juice…
I ordered the C8F host (and 2 spare MCPCBs), so I don’t have their driver. But this host really has grown on me:
3p-setup, DTP copper MCPCB and really flat surface in the head, reflector and MCPCB are tightened with a screw from the inside, lots of room for the driver, an easy to press sideswitch with a crisp click, driver retention ring, enough space for a protected cell, squared threads on both sides of the tube, anodized threads at the tail for lockout, flawless anodizing. And the spare MCPCBs came with a foil on the copper side for protection.
Sofirn did a lot of things very, very well on this one. :+1:
Let’s get cooking :partying_face:
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Looks great. I will be looking forward to seeing your results. Yeah, djozz took care of us with his group buy for filters. I couldn’t find anything when I looked around so resorted to rolling my own.
Reflowing went well and I did find my spare LD-1.
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All three lighting up evenly (this is with a cell at 3.25V resting).
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Installing into the C8F host was easy. With the LD-1 I went for 3 mode and de-soldered moon.
I’m just not sure the beam is looking as it is supposed to look.
The center is yellow, then some dark area, followed by a blue corona.
Did I already wreck the LEDs or is that ok that way?
(Still without djozz’s filter)
.
Edit: The center seems to be the ‘good’ part with the most UV radiation. It’s really fun to play with. Now I’m curious which effect the filter will have.
I think the 365nm light exits the dome of the led quite differently as the visible light (the refraction is fairly dependent on wavelength and 365nm is quite far from the average visible light) , resulting in a different focal point, this becomes more apparent with smooth reflectors.
Just this afternoon I made a C8 with the same led (but just one) and using a standard center piece the hotspot was pretty ugly. It improved when I sanded the centerpiece thinner, just like when using domeless leds compared to leds with dome.
This is pretty interesting, I will look into it a bit more precise this evening.
That’s what mine looked like too. I agree with djozz that the visible light makes that yellow center. The ZWB filter cleans it up nicely. I notice the “petals” around the edge of the spill due to the three reflectors more than with a single emitter. It is fun, isn’t it!