UV triple using Sofirn C8F

Very nice Scientist! Thanks for sharing the great info, sweet build, and interesting site. I would love your light in the woods at night! So many interesting things can be found with my S2+uv that I never even knew about, like big millipedes fat as a pencil and two or three inches long. I think the danger of using these lights outside in a natural setting are way lower than inside, where there are more reflective surfaces. Still, it’s a good idea to be wearing glasses, especially with that awesome triple. As to not needing a bright uv light, you don’t, until you get a decent one, that is. Then it’s flashaholism as usual.

Cool :+1:

Quest for far UVC not working out well.

From further reading, 222nm appears to be the wavelength I need. I believe 207nm works, but for an unknown reason 222nm is better.

I have pretty much abandoned the search for LEDs in this range.

The only source that seems viable is from Kr-Cl gas excimer lamps using a filter. It is relatively inexpensive. Uses high voltage, which can be generated by a small power supply. But the manufacturer will not sell me one of their development kits.

Alternety I am so sorry for your ongoing health issue. Here is the problem:

Presently UVC leds have much poorer quantum efficiency (by several orders of magnitude) than the 365nm variety. This is due to the much higher number of defects in the short wavelength leds compared to the longer wavelengths. You are just a little ahead of the curve on needing the really short UVC leds. But with the rapid development of these leds I hope to see some commercially in the near future. Little comfort for someone who has an existing health issue and needs something now. You can get a KrCl light source for relatively cheap on ebay if you are lucky https://www.ebay.com/sch/i.html?_from=R40&_trksid=p2380057.m570.l1313.TR0.TRC0.H0.Xexcilamp.TRS0&_nkw=excilamp&_sacat=0 (search for Excilamp on ebay).

There is a nice application note from Crystal IS here you might like to see that gives a table of UVC effectiveness for various bugs http://www.cisuvc.com/content/documents/files/UVCLEDsforDisinfection.AN1.pdf

You may want to have a look at swimming pool UVC desinfection technology. It uses incandescent (?) light tubes that emit 253.7 nm, made by Philips.
I have seen up to 25 W effective UVC at 75 W electric.

Thanks Scientist.

TBone - Thanks, but it has to be 222 nm.

Nice build! I wish someone sold the correct glass as round lenses, I can only find squares or 22mm diameter circles.

djozz found some on Kaidomain http://kaidomain.com/p/S027557.42mm-x-1_5mm-ZWB2-UV365nm-Ultraviolet-UV-Filter-for-365nm-UV-LED-Flashlight.

Thanks for the inspiration Scientist and the testing Djozz, I just built one of these after using S2+ UV builds for the past few years. I cant believe the difference, I use florescent dyes to find leaks in roofing and waterproofing and the throw on the C8f UV build is simply amazing. Cheers.

Good to hear of some functional use of this weird washout of the flashlight hobby.

I still have to build my C8F UV triple, maybe if I have new money I can use the newly listed (but already a few years in production) 1500+ mW LG leds from the Convoy store.

Great to hear. I like how compact it is too. I hardly notice it when I have it on my belt.

Also I did this before djozz finished his tests. He showed there is a more efficient UV emitter than the SST-10. Also there is now a C8F that uses a 21700 battery for longer lifetime. So I would probably do things differently now.

I ordered 3 seoul viosys and the 42mm ZWB2 filter from KD. The lower Vf of these LEDs means a lot of output when used with a FET driver.

I was using my UV S2 on the beach a while ago. Pretty fun to see the world with this altered light. Crabs fluoresce white and some seaweed glows bright orange. Looking at broad landscapes like this, I would have appreciated the extra output and beam intensity of my soon-to-be modded UV C8F.

I wondered if the crabs can’t see the UV. You could see them glowing a ways off but they wouldn’t move much until you got close to to them. You should be able to find some fluorescent calcite in OH.

I also used the 3 seoul viosys/ 42mm ZWB2 filter from KD. I was shining it on turbo on my wrist and could feel heat after a few seconds. I’m pretty sure it would give you a nice sunburn if left for very long, I could feel stinging for about 10 minutes after.

One thing I did notice was that I wanted an illuminated button, since your stumbling around in the dark when you use this light. Connecting the unused pad on the e-switch to the + e-switch terminal turned on 2 nice little green lights beside the switch ! Replaced the black rubber boot cover with a opaque one and it lights up nice.

Djozz do you think those new LG dies will put out even more UV than the seoul viosys with direct drive ?

I have a few of those new leds on order, after they arrive I know for sure, but the specs are better than from the Seoul Vyosys leds. The throw may be not as good because the seoul leds have fairly small dies and these LG leds have larger dies.

One thing about this Seoul Viosys led, I do not test for that but pirateo40, who uses UV light in a continuous way for mineral lighting, reported that this led holds up less well over time than the 3rd gen. LG led that Convoy was selling (the new LG led that I have on order are 4th gen.).

Awesome thanks, Looking forward to your updated testing results

I'm trying to join this camp, too...right now I'm struggling with driver choice. What did you guys end up with? At this point I'm thinking of a 20mm 7135x6 or something in that max range from Richard with hopefully some ramping firmware. It doesn't look like there's any way to keep the side switch functions on this light without overdriving the emitters...? I'll be putting in the LG 365 from Simon and I guess they're more resilient than the Nichia but I still don't want to fry them, so I'd prefer a dedicated driver instead of sticking with the stock Sofirn ramping with caution. I picked up the filter from ali at this store. Was a bit hesitant at first but they look a) scientific and b) legitimate even though they have not been on the site for very long. They do charge for shipping but I had the glass in about 3-1/2 weeks with that slow economy air mail shipping, surprisingly (E-packet is a buck more and wasn't available when I ordered). Great quality lens, nicely finished and accurately sized, and they packed it very well for shipping.

Tangsinuo store - ZWB2 365 42mm * 2mm

Bribo, where did you find the boot for the side switch? Everything I could find that was small enough was also too tall and looked like it would be too thick on the flange. I put a blue boot on the tail and would like to try to find one for the side, too. Great mod on the switch leds...I've been thinking that it would be smart to have something lit on this while in use just in case of a drop & tumble.

yep i have 2 that i use for uranium (aka depression and vaseline) glass collecting

note that there are pretty good $3 UV zoom 1xAA lights available, too

another note, that ZX glass filter stuff works but it is very soft and chippable.

wle

Translucent Boots:
https://www.aliexpress.com/store/product/Different-button-rubber-tips-for-sofirn-flashlight/2933049_32833386523.html?spm=2114.12010612.8148356.30.4c0511963KlYbx

When you order you need to specify in comments- translucent rubber cover for e-switch for C8F (not black)