Dive lamp project for underwater bio-fluorescence

LarsB

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Dear divers and flashaholics (I'm about to become one myself, this is my third lamp project, actually!),

I am currently working on a dive lamp for watching underwater bio-fluorescence.
See http://guest.engelschall.com/~sb/fluo-diving/ for a detailed collection of information about this latter topic.

My current project is technically inspired by forum user horstartur's lamp;
see http://www.candlepowerforums.com/vb...ence-in-night-dives-with-HiTecLEDs&highlight=
and http://www.uni-due.de/zoophysiologie/Seiten/GRUNZScuba2.HTM

My lamp is based on a dive torch from the same manufacturer as his, www.tillytec.de
However, it uses ultraviolet LEDs (four NC4U133A from Nichia), whereas horstartur uses blue LEDs from OSRAM.
This has the advantage that no filters are needed for the camera and the mask.

You can see some pictures showing the progress of the project (think of it as a photo blog) here:
https://picasaweb.google.com/110815712949417343579/HowToBuildYourOwnUltravioletDivingLamp3

Any comments or suggestions are welcome!

Best regards,
LarsB

P.S.: For my previous two UV dive lamp projects, see here:
https://picasaweb.google.com/110815712949417343579/HowToBuildYourOwnUltravioletDivingLamp2
https://picasaweb.google.com/110815712949417343579/HowToBuildYourOwnUltravioletDivingLamp
For some of the results, see here:
https://picasaweb.google.com/106199910917431710533/Hurghada2011
(lamp #2 with two NCSU033B UV LEDs from Nichia)
 
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jspeybro

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subscribed :)
I'm going to do something similar but am still looking around for the possibilities.
Where are you getting these LEDs from and at what cost?

I did a small test in local waters with a royal blue LED but I didn't have any filters yet so it wasn't very impressive (and probably there aren't too much fluorescent species in the Dutch waters), but I'd like to have something going when going to Egypt next year.
I'm also going to test 400nm LEDs but I'll most likely still need a filter since this is at the edge of the visible.

I see you're adding a battery protection circuit which makes sense when you can hardly see the light from the LEDs (only a faint glow).
It's a pity that these 365nm LEDs are so expensive :(

nice collection of info you gathered there on your website!
 

arek98

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Hi Lars

This is a great project. Lots of power in that light too.

Question, why did you choose 365nm? Did you try 395nm? Green fluorescent proteins have two major excitation peaks. One at 395nm and other at 498nm. Did you try 395nm and decided that 365nm works better?

Do you see any effect during day dives? I installed NCSU034B (395nm) in Ferei W150 as a proof of concept. Driven by GD500 buck/boost converter (GD500 means 0.5A) + MOSFET to turn it on/off with original ring. Replaced original reflector with Rose NIS033U series optics (FA10911 - 10 degrees FWHM).

So far I had it only on two day dives and I didn't see any effect. I'm wondering if it does not work at all (395nm being not good), has not enough power, or just fluorescence being to dim to be visible with daylight present.
 

LarsB

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subscribed :)
I'm going to do something similar but am still looking around for the possibilities.
Where are you getting these LEDs from and at what cost?
Directly from Nichia Nederland BV via their contact form at https://www.nichia.co.jp/en/contact/inquiries.html
I paid 90.90 Euros per piece (NC4U133A). I paid 81.82 Euros per piece for the NCSU033B last year.
I did a small test in local waters with a royal blue LED but I didn't have any filters yet so it wasn't very impressive
I also have a lamp (from Hartenberger) with blue LEDs. Without filters, you only see blue everywhere; but no fluorescence, because it is overpowered by the blue light.
Which is logical, energy decreases in the process of fluorescence. So without filters, you stand no chance of seeing anything worthwhile.
(and probably there aren't too much fluorescent species in the Dutch waters),
There are not as many and they are not as spectacular as in tropical waters, but there are.
All algae either glow in orange or red, for instance. And shrimp (garnaalen) also fluoresce a bit; at least you can see them in the UV light,
whereas in normal white light you don't, because they are transparent. I also found a "zeenaald" thanks to the UV light, which I would
otherwise have mistaken for seaweed. And I saw tiny little polyps (maybe 1-3 mm) opening and closing rhythmically like umbrellas, which were also
transparent in white light.
but I'd like to have something going when going to Egypt next year.
See my results from Egypt here: https://picasaweb.google.com/106199910917431710533/Hurghada2011
I'm also going to test 400nm LEDs but I'll most likely still need a filter since this is at the edge of the visible.
I tried a LED with 395-410 nm and the results were appaling (namely zero!).
Maybe it's not a good wavelength, or maybe you need filters, or maybe my lamp was just not powerful enough (1W).
I see you're adding a battery protection circuit which makes sense when you can hardly see the light from the LEDs (only a faint glow).
You actually can, because of fluorescence of the water itself and of the silt suspended in the water.
See https://picasaweb.google.com/110815...OwnUltravioletDivingLamp2#5613393573814560450 for a photo,
and see The inherent visible light signature of an intense underwater ultraviolet light source due to combined Raman and fluorescence effects for why.
It's a pity that these 365nm LEDs are so expensive :(
Indeed!
nice collection of info you gathered there on your website!
Thanks! :)
 

LarsB

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Hi Lars
This is a great project. Lots of power in that light too.
Thanks! :)
Question, why did you choose 365nm?
Because this was the only true ultraviolet wavelength, as far into the UV spectrum as possible, for which I could find any (affordable) LEDs.
There may be LEDs for smaller wavelengths, but I did not find them, and they will probably be even more expensive than the ones I use.
I also wanted to be as faithful to my inspiration, the book "Dolphin Island" from 1963 by SF author and diver Sir Arthur C. Clarke, in which diving with ultraviolet lamps was described.
Did you try 395nm?
Yes, but either my lamp was too weak (1W), or you already need filters (because it's almost in the visible spectrum), or it's a bad wavelength for underwater fluorescence.
Either way, I tried, but didn't like the results (none).
Green fluorescent proteins have two major excitation peaks. One at 395nm and other at 498nm.
I know, but GFP is only one of many different fluorescing proteins found under water!
Did you try 395nm and decided that 365nm works better?
Yes, exactly.
Do you see any effect during day dives?
I never tried, at least not on a spot with lots of underwater life (such as Kerkweg/Den Osse, Zeelandbrug).
Oostvoorne for instance is the last place you'd want to test your UV torch, for lack of underwater life!
Since in dutch waters every dive during the day actually turns into a night dive below 10 m or so, due to low visibility, you might as well try during the day.
I installed NCSU034B (395nm) in Ferei W150 as a proof of concept. Driven by GD500 buck/boost converter (GD500 means 0.5A) + MOSFET to turn it on/off with original ring. Replaced original reflector with Rose NIS033U series optics (FA10911 - 10 degrees FWHM).
Sounds great! Do you have any pictures?
So far I had it only on two day dives and I didn't see any effect. I'm wondering if it does not work at all (395nm being not good), has not enough power, or just fluorescence being to dim to be visible with daylight present.
All of these reasons are possible, also in combination!
 

jspeybro

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So far I had it only on two day dives and I didn't see any effect. I'm wondering if it does not work at all (395nm being not good), has not enough power, or just fluorescence being to dim to be visible with daylight present.
I'm suspecting the last. Fluorescence is a few orders of magnitude less intense than the excitation light. That is why you should use a filter to block the excitation light because it will overpower the fluorecent light.
 

OS74

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It would be interesting trying a cheap 1W UV drop-in module to just see what happens. What would be a sufficent excitation filter? Would a ordinary gel filter from my strobe-kit do?

Cheers
/O
 

jspeybro

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since Leds typically have a bandwith of about 30-40nm, you'll need any kind of longpass filter that blocks the light of the LED plus some margin. If the LED is 395nm, expect it to also give light up to 405-410nm so you'll want a longpass filter with a cut-on wavelength around 415-420nm (at 50% transmission). unfortunately this info is more than likely not available for gel filters so you'll have to try it out I guess. Typically yellow filters will block most of the blue which is up to about 500nm. While this can work fine, you'll miss the blue part of the fluorescence. But it may be a nice place to start and experiment ;-)
 

jspeybro

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I never tried, at least not on a spot with lots of underwater life (such as Kerkweg/Den Osse, Zeelandbrug).
Oostvoorne for instance is the last place you'd want to test your UV torch, for lack of underwater life!
Since in dutch waters every dive during the day actually turns into a night dive below 10 m or so, due to low visibility, you might as well try during the day.
ah these dutch waters :thumbsup: even though I'm Belgian :sssh:.
I must say that 'zeenaalden' indeed show some fluorescence (Bruinisse), even with royal blue leds (450nm) and without any filter. Other than that, the material used by different species to attach itself to rocks (like mussels at Anna Jacobapolder) also shows white fluorescence
 

LarsB

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It would be interesting trying a cheap 1W UV drop-in module to just see what happens. What would be a sufficent excitation filter? Would a ordinary gel filter from my strobe-kit do?
Cheers
/O

I tried just that, took a drop in module (http://www.taschenlampen-papst.de/P...ontrolle-Rissdetektion-Leckageortung-Forensik), took the LED out, and replaced the white LED of a LED Lenser Frogman dive lamp with it. I only had to adjust the resistor from 3.3 to 8.2 Ohms.

However, as said above, the results were not convincing (to say the least).
Either it was the wrong wavelength, or it was too weak (1W).

Even with my second lamp with 6W I had troubles with my camera: the fluorescent light was too faint for the autofocus to work.

This is why I'm now switching to more powerful lamps (60W, 48W).

Wrt excitation filters:
NightSea can deliver dichroic excitation filters cut to specification; see http://www.nightsea.com/photoblue_ms.htm

Excitation filters
Use with ...Price
BECUST
Custom-cut sizes and shapes$50 and up

Cheers!
 
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arek98

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Do you have any pictures?

I was wrong saying that my light is 395nm. It is 385nm (NCSU034B)

I don't have pictures from build but this is how it looks now.
FUV1.jpg

FUV2.jpg


This is original heatsink/driver holder from another light. There was a reed switch in groove on the side. I replaced original one which was glass with one that has plastic molded body. Then I needed to add MOSFET and resistor to turn on/off GD500. I removed all components from original driver and used board for contact only. It was tight fit, GD500, resistor and MOSFET inside.
FUV3.jpg

FUV4.jpg


Optics itself
FUV6.jpg

I had to file corners a little to make it fit inside Ferei head.
 

350xfire

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Seems like I read somewhere that shining UV lights at coral is bad...
 

jspeybro

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I think that depends on the wavelength, just like you need to protect yourself against the UV of the sun. The wavelengths used here are not so agressive as 330nm and shorter wavelengths.

anyway, fluorescence is just a process that happens at the electronic level of some molecules, there's no damage involved in this process. in some cases of non-living tissues, fluorescence can fade away though but that is mainly a problem if you use fluorescence for analytical measurements
 

LarsB

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Seems like I read somewhere that shining UV lights at coral is bad...
This has already been discussed in some other forum (can't find it back right now though);
and the conclusion was that the energies involved were infinitely smaller than the amounts of UV radiation coming from the sun.
Not to mention the fact that the lights were shone on the corals only a couple of minutes at most.
 

horstartur

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I use for a long time blue light with 450-465 nm. I received muchbetter results than other people with UV or near UV wavelenght. Charles Mazel also a pioneer in underwater fluorescence also uses blue light. My results you can find on YouTube > Links on my homepage > http://www.uni-due.de/zoophysiologie/
I know about the discussion that with UV you do not need additional exitation filter nor a yellow filter on the mask. So the people would be happy to discard any additional equipment. Anyhow the modified GFP in corals react very strong on wavelenght around 450 nm. Some theory you can read in articles on my WEB-page and also in pdf-Files for download.
 

globalmark

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Hi Guys
I have also made a Bio-Fluorescence light , a cree module that fits in my old SL4 - bit of a tight beam but worked great ,
used a cheap Cree XTE Royal Blue led 450-460nm and yellow filter material that i bought from Charles Mazel (didn't buy specific filters just material- as worked out cheaper and the yellow is just acrylic so easy to cut with a fretsaw and sandpaper and got enough to make camera and mask filters), think you can also use old yellow camera filter or yellow acrylic..
Led's only few dollars each so bought a few and playing with them see how it go's but they are definately bright enough for this ..
Mark
 

jspeybro

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I just did a night dive last night in Egypt, using my 15W 395nm leds. The corals gave a nice green fluorescence. I didn't need a yellow filter to see the fluorescence. worked very nice.
 

LarsB

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If you want to see what underwater fluorescence looks like (which is what I was using the Nichia UV LEDs for),
and why some people say that it is like being in the movie "Avatar",
have a look at this video of mine:
http://www.youtube.com/watch?v=4V9TCdCbX6U
This video was made with blue light (around 450 nm) instead of UV, however,
because, as I found out by trying, the fluorescence is much stronger with blue light,
apparently because marine life has adapted to the properties of water,
which is more transparent to blue light than it is to UV.
Enjoy!
 

jspeybro

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nice video. 450nm seems to work better. I'm assuming you used a yellow filter to block the blue light. with my UV lamp, I could only see the green fluorescence. You seem to get blue and red as well. Is this visible with the eye or only on camera?

I think I'll change my light to use blue leds instead of UV...
 
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