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DIY Handheld 325 lumens dive light

Discussion in 'Do It Yourself - DIY' started by gcbryan, May 10, 2010.

  1. gcbryan

    gcbryan One Bad Hombre

    # of Dives: 1,000 - 2,499
    Location: Seattle
    15,793
    9,689
    113
    This is a light I came up with as an experimental test (dive) light. The first picture is of the front and the second is of the tail with a pen in the picture for size reference. They are not great pics but perhaps are adequate since you can't really tell much about what I've done from pics anyway.

    In the second picture it looks like you are looking at a green light but it's actually just a glow in the dark switch cover I used. When I took the picture the flash made it look more like a light.

    This light costs no more than $25 or so to make, it runs on (1) 18650 li-ion cell (rechargeable). I've tested it down to 100 fsw. This is not a perfect light in that after a certain depth you can't turn it off. Around here that isn't a problem however.

    If I continue experimenting with it I'll address the always on issue. You can turn it off and use it as usual when not in the water of course.

    I already have plenty of dive lights so this was to test a few concepts. I like the idea of having small lights that can be mounted hands-free whether using an Oxycheq Softsock or a homemade version that is similar. I like the idea of taking a stock light and by choosing the right one having to modify it as little as possible.

    I've been a little more cautious this time around with the experiments only because the parts I use while not expensive take forever to obtain (Hong Kong).

    This light looks stock even after the changes and in fact I intend to mainly use it as a non-diving flashlight after I test it in the water a few more times. It is an exceptional light in its own right as a general purpose flashlight.

    It outputs 325 lumens (emitter specs so no guarantees there) on high, 120 lumens on medium and 3 lumens on low. I've replaced the standard tail switch with a momentary switch that clicks to the "on" position as well.

    This means that water pressure turns it on and not off. I removed the lens retaining ring from the head, took out the glass lens (very thin and no room for a thicker one so 100 fsw is all I'm going to test this one to) and added a 30 mm o-ring to the ledge on which the lens rests. I then put everything back together.

    As mentioned I took apart the tailcap and replaced the standard switch with a "forward clicky" switch. It wasn't an exact replacement part but once it was installed the stock switch retaining ring held it firmly in place.

    Before finishing up that I popped out the tailcap cover and replaced it with a green GITD version. I added some marine grade silicone sealant to the top surface of the tail cap flange. This is the surface that would mate to the inside of the tail of the flashlight. The threaded washer retaining ring applies pressure from the inside as well. I put a little in the hole that the cover button pops through too.

    This was it! The light was $23 plus battery ($4) and a couple of dollars worth of silicone sealant, o-ring, tail cap button (not necessary) and a $2 switch replacement.

    The light uses a Cree XP-G R5 led rated to output 325 lumens with a current draw of 1A.

    I tested another small non-dive light earlier (last year) where I had to make a few more extensive modifications...made the tailcap solid with epoxy and used a lot of sealant in front of and behind the lens with a similar result. That light went to 100 fsw as well.

    So, in effect I'm collecting data points (experience) with exactly what causes lights to flood and what isn't a big problem. I picked this light because there was a ledge for the lens to rest on among other reasons. I simply had to add an o-ring and deal with the switching method and with sealing.

    FYI-the are two small holes in the side of the tail cap so you can fashion a way to attach a boltsnap or lanyard.

    Another reason I picked this light is that led "drop-ins" are commonly available. If I decided to replace the XP-G led with a smaller beam but one that might punch through limited viz waters a little better I could do that as well for the cost of an $8 drop-in.

    Future improved led's could be easily added this way.
     

    Attached Files:

  2. nwbrewer

    nwbrewer Barracuda

    # of Dives: 200 - 499
    Location: Woodinville, Wa
    291
    5
    18
    Gray, which 6p clone is that? I've been thinking of doing the same thing to use as a backup light. What do you think about replacing the clicky switch with a piezio and MOSFET or something? That way you wouldn't have to worry about pressure turning it on, and it would be permanently sealed at the switch (JB weld or something to hold in the switch)
     
  3. gcbryan

    gcbryan One Bad Hombre

    # of Dives: 1,000 - 2,499
    Location: Seattle
    15,793
    9,689
    113
    It's Uniquefire L2 and comes with a XP-G R5 for $23 and you can get a XR-E R2 drop-in for $9 if you prefer.

    I don't really have much in the way of electronics and soldering skills. I've tried but due to the small parts and my soldering skills...let's just say that I'm not there yet. :)

    I would prefer to have a magnetic switch (reed or hall effect) but I don't have the skills to pull that off. Space is limited in there as well.

    In another project that I posted on here a while back I took a similar light (but it wasn't a P60 host) and using epoxy turned the clicky switch tailcap into a solid tailcap and just used it as a "twisty".

    That doesn't work with P60 hosts however since they use drop-ins and nothing is fixed inside. To twist the tailcap enough to turn a P60 off you would basically have the tailcap fall off.

    A P60 with a magnetic switch would be much better. To use as a backup it would be necessary of course. It would also be nice to put thicker glass for the front lens. That's a limiting factor now. There's limited room though. You could double the lens up and they would fit but the retaining ring would not be able to screw on more than a turn or so.

    You could still do it and just not rely on that ring. You could use a little sealant around and behind the lens and use epoxy to affix the ring in place and not rely on a longer threaded section.

    Since I didn't have the means to add magnetic switching on this light I didn't make any drastic changes to the lens since I knew as soon as I was through testing it out I was going to reconvert it for above water use as this is the perfect flashlight for me for that use.

    If you make a P60 backup dive light be sure to post with details and pictures. I'm surprised no one makes a P60 dive light. Upgrading or just simply changing leds would be simple. I can use a XR-E R2 on one dive for more throw and a XP-G R5 on another dive for more light on the wall or where ever I'm diving. It would be nice to have an aspheric lens with spacer that could replace the screw-in reflector and yet be converted back easily.

    If you drove the XP-G at 1.5A or above considering that you're in water that approaching primary dive light range. Certainly brighter than most of the stuff sold in dive stores (excluding cannisters).

    Edit: I should add that I have read about people trying a piezo and mosfet and although it can work of course I think they were having problems with triggering it back off (I can't remember the details and don't totally understand it anyway).
     
    Last edited: May 12, 2010
  4. nwbrewer

    nwbrewer Barracuda

    # of Dives: 200 - 499
    Location: Woodinville, Wa
    291
    5
    18
    Thanks! The people who were having issues with the particular MOSFET had ordered one that was cheap and easy to get, but was out of spec for what they were trying to do. I'd love to see somebody with the machining skills make basically a Salvo Rat jr. designed to take a P60 drop in. That would be such a great platform for upgrades as you mentioned. Looks like I'm off to Dx.
     

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