DIY UV dive light

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naimis

Contributor
Messages
134
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Location
Central Texas
# of dives
100 - 199
Hey, folks. I've been working on building my own dive light specifically designed as an exciter for the green fluorescent protein present in many underwater critters. The prototype was made using a UK SuperQ eLED as the body and optics. I won't be using that as a prototype anymore, however, as the soldered leads on the LED I put in ended up scratching up the reflector a bit.

The LED in the prototype was a LedEngin LZ1-30UA05, which is the best ... well, to be realistic, ONLY LED I could find that was 1W or greater that emitted at or near the desired wavelength of 395nm.

The prototype worked pretty well, I've attached a picture of the light and the one salvageable picture I took using it, of a fluorescing anemone (the green of the anemone is its fluorescence, the purple is from the light). It was hard to get good pictures as 1) it only is visible when there's no white light around, whether it's coming from the sun or another diver's light, and 2) I didn't have the UV light mounted on the camera housing like I should have. The end result was a set of pictures that were either too dark or really blurry from being shaken around by the Cozumel currents.

The next revision I was planning on doing, I was originally planning on using a UK C8 and replacing the LEDs in the head. This would be kinda tricky, though, given the way the C8 head is assembled (you have to desolder the LEDs just to get the head apart).

I'm currently reading up on people's DIY canister lights, and those are appealing to me quite a bit. They sound relatively straight-forward to put together, and not overly expensive, either.

Anyway, just thought I'd stick my head in and let people know what I'm up to.
 

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Keep up the good work...I think you have something there.

U/O
 
I got the first batch of parts in this weekend, consisting of a lens/reflector, LED, driver, MOSFETs and reed switches. I had to order the parts from three different vendors due to limited availability :-/ but so far, it's:
LLSP-1T06-H (LedEngin reflector/lens, $3)
LZ4-40UA10 (LedEngin 10W UV LED, serially connected MCPCB w/ 4 emitters, $110)
2008B-700 (LEDdynamics PowerPuck driver, 700mA, $20)
KSK-1A35-1520 (Meder Electronics reed switches, $0.60 ea)
SPP08P06P (Infineon MOSFET)

I have a circuit diagram that a buddy did for me, but it currently only exists on my whiteboard at the office. I'll see if I can't get a circuit diagram tool and post an image later. In short, the purpose of the MOSFET is to keep the higher currents that the driver uses from going through the reed switch. After actually wiring up the driver with the LED, however, it seems somewhat unnecessary - the switches are rated for at least 1A and the current draw was less than .5A.

The batteries I'm planning on using are 18650s (Li+), and I'll be sticking with the original plan of 6 cells (22.2V) even though Vfwd on the LED was measured at only 14.5V. There are a variety of reasons, including run time, battery heat, and packaging. Another buddy has those, and I hope to be able to get them in my hands this week and start putting the pack together. Can anyone recommend a good pack charger/tester? I prefer one with an A/C source given my usage patterns (overnight charges in hotel rooms or live-aboards :).

The canister I'll probably make out of PVC, with clamps and glands from Oxycheq (no particular reason for those choices, just convenience). The head I'll make out of aluminum (6061 alloy no doubt), or, to be more accurate, I'll have the battery buddy use his skills and shop to make it for me :).
 

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After several false starts (see pictures), I've finally managed to assemble the battery canister. I haven't put the electronics together yet, but that's next, with the machining of the light head to be done as I can (having to rely on someone else for that).
 

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Finished machining the light head last night, and I'm hoping to get some leak testing done today (or at least very very soon). I'll post pictures later (I can take all the pictures I want, but unfortunately, my laptop is just about dead so I can't transfer them easily).

I ended up using 2" PVC instead of the original 1 1/2" PVC, which was too small for the batteries once they were wrapped. When I went to get the 2" PVC fittings, I happened to see a 1 1/2" Clevis pipe hanger in a nearby bin, which turned out to be the perfect thing to hold the lamp head onto the Ikelite strobe arm. Again, I'll post pictures as soon as I manage to get them off of the camera :). In any case $1.75 is a much better price than ~$40 for Ikelite parts.
 
Matey - if you want something a bit smaller - you can get 395nm 1W LED R2 drop ins from deal extreme....

these will fit into a UK SL4 (see the thread about converting SL4 to LED)

I have one of these - have not had the opportunity to test at night underwater,
but finds plenty of bugs in the back garden!


BTW - very neat looking canister - would you be able to post some bigger pictures, or a breakdown of how you built it? (i would like to shamelessly plagiarise)

cheers,
 
Matey - if you want something a bit smaller - you can get 395nm 1W LED R2 drop ins from deal extreme....

these will fit into a UK SL4 (see the thread about converting SL4 to LED)

I have one of these - have not had the opportunity to test at night underwater,
but finds plenty of bugs in the back garden!


BTW - very neat looking canister - would you be able to post some bigger pictures, or a breakdown of how you built it? (i would like to shamelessly plagiarise)

cheers,

I built a prototype using a 5W LED and found that even that left a lot to be desired in terms of emitting enough photons to make the critters glow enough to get a decent picture (VERY low light), so I decided to move up to the 10W for this rev.

I can post pictures (originals can be found at Dive Light pictures by naimis - Photobucket though as I said, I don't have any really current photos. I didn't do any of the machining, and the design for the head was "back-of-a-napkin", essentially, but I'll post what I have at some point.

Ok, I see you're actually asking about the canister, not the light as a whole. Yeah, I can do that, it's pretty easy. The last one I made took less than 2 hours start to finish. I'll do it later.
 
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With both my laptop and my card reader out of commission, it's going to be a while before I can post pictures. In the mean-time, here's a verbal description of the canister.

Use 2" PVC. I tried using 1 1/2" PVC, which was big enough for the three 18650 Li+ batteries, but once I had put shrink-wrap on them, they wouldn't fit. These instructions assume sch40.

Take a coupler fitting and using wet/dry sand paper that's been soaked in water, smooth out one edge of the fitting, starting at 180 grit and gradually moving up to 600 (I had 180, 220, 320, 400, 600).

Put a cap on one end of the PVC pipe, and the sanded coupler on the other, leaving the smooth end of the coupler facing away from the pipe.

When joining PVC, make sure to clean it first using PVC cleaner, and put cement on both surfaces, all the way around. Push the two pieces together while twisting, and hold them together for a few seconds (say, 20). If you don't hold them together, they'll tend to push away from each other.

To make the lid, I used a 2" PVC plug. This is like a cap, but instead of being a fitting that goes around the OD of the 2" PVC pipe, it's the same OD as the pipe, so it goes inside a fitting, specifically the above coupler. The most important feature of the PVC plugs is that they have flat ends for the cable gland to seal against (though not so flat that they can be used as-is without sanding).

I had a fair amount of trouble drilling a hole to tap for the cable gland, so you'll probably want to do this as early as possible. Use a drill press and hold the piece in place by drilling a hole in a scrap of wood big enough for the bit (I used a hole saw that cut a hole big enough for the original 1" PVC plug that I was using before I switched to 2"). Clamp that piece of wood down to the drill press table with the piece underneath so the scrap is pressing down on the piece. DO NOT CLAMP FROM THE SIDES. That will only result in a mess as seen in my earlier pictures. When drilling, use a slow bit speed and a slow feed rate. If you go too fast in either, you'll have a mess.

Once the hole is drilled for the tap, go ahead and smooth out the top for the O-ring seal on the gland, use the wet sanding method described above.

You'll need a ring on the plug for the o-ring seal to push against, so get a 2" PVC fitting (coupler is probably easiest) and cut off a piece long enough to provide a ring around the plug (I used a 20mm length). It's a good idea to cut this straight, so you can either use the method described elsewhere on this forum (paper wrap), or a miter box. I used a miter box. When holding the piece in a miter box, you'll want to be holding it both down and to the back of the box.

This cut ring will need to have a smooth edge for the o-ring, so sand it smooth as above. Glue it onto the plug, but only put PVC cleaner and cement on the top-most portion of the plug - you don't want any on the part of the plug that will be inserted, dry, into the coupler on the pipe.

At this point, where the ring is, you should have a ~8mm thick wall. Use a drill press to drill out holes to tap for your latch screws. I used the latches that Oxycheq sells and #6 screws. My recommendation is to drill a 6mm hole for a 1/4" screw. Do one hole, tap it out, screw the latch piece in (I put the hooks on top and the latches on the main body), then mark and do the next hole for that part. You may have better luck using the paper cuff method, here, as far as getting everything parallel to the edges. For the lid, I just used an ordinary drill press vise to hold it in place, with wood scrap to keep the metal from scratching up the smooth lid. For the holes on the main body, I used a jig I made by doing v-cuts into scraps of wood, setting the pipe into the Vs and clamping it down in the middle.

Depending on the latches you get, you may find that you have to cut off a short length of pipe to glue inside the bottom of the 2" PVC coupler that's on the main body to provide a thicker wall for the screws to bite into. Again, don't put glue anywhere you don't want it to be when you're all done :).

If you have questions, feel free to ask. I'm going to update this later, once I have a laptop with a card reader that I can use to upload pictures with (do laptops go on sale on "Black Friday"?).
 
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