I want to make a dive light.

[Hashime]

I want to make a dive light to use on my open water certification dives coming up in late august. I just want to make a simple yet powerful LED torch that will allow me to see a moderate distance underwater.
For housing I was thinking or using either schedule 80 or steel piping, I have access to and the tool required to work both.
For power I was thinking or using a NiCad RC car battery that I have kicking around, just re-arranging the cells to fit the tube. I am proficient at soldering and have some good help for circuit design, so power is not an issue.
To switch the light I was planing to use a reed switch to reduce the number of seals required.

The main thing I need help with is deciding which LED lamps to use, and how to mount them. (I was thinking either Plexiglas glass front piece, or putting holes in a cap and gluing them through)

Thank for the help.

 

[DM51]

Welcome to CPF, Hashime

We have a Dive Lighting sub-forum, so I'll move your thread there.

Just a thought - if you are about to do your OW certification, my advice would be not to take extra equipment with you, such as dive lights (unless you are doing a night dive). You'll need to concentrate on your basic skills.


Edit: I see you posted a 2nd identical thread here. I've deleted it. Cross-posting is not permitted (Rule 9).

 

[350xfire]

Agree with moderator. Learn how to dive first, then get a light...\

BTW, steel canister totally worthless for water. Need aluminum, PVC, Delrin or some other plastic.

For a first build, keep it simple. You can go to dealextreme.com and get a fully build LED/reflector/driver module that, with some massaging, will fit in a Maglite. Do that and use a canister to house the batteries.

 

[Hashime]

Welcome to CPF, Hashime

We have a Dive Lighting sub-forum, so I'll move your thread there.

Just a thought - if you are about to do your OW certification, my advice would be not to take extra equipment with you, such as dive lights (unless you are doing a night dive). You'll need to concentrate on your basic skills.


Edit: I see you posted a 2nd identical thread here. I've deleted it. Cross-posting is not permitted (Rule 9).

Sorry about that, I didn't see the thread show up immediately, and assumed my browser malfunctioned. (My previous forum experience was with an "un-filtered" style of submission) It will not happen again.

 

[BOHUNTER]

Hey Im in for Building DIY Dive light. I found half a Mastodon tooth and two broken Auriculatis teeth Friday in the Flint River in Georgia. Luckily the water was clear enough ambient light was penetrating deep enough for me! I dive other rivers where this isnt an option. I purchased the 50 watt 12V but its 11lbs of battery. No big deal but If I can cut down the weight thats good because I have to off set it with lead on other side.

Im ready... anxious... Im sure as this guy dives more he also will be ready to find a new source of light. I started out with 2 PClites and I can tell you in black water you may as well be blind. Im swimming with gators and big turtles, Id like to see them first actually!

I can purchase new 12V battery packs but alternative to halogen with hotter white light and less of a battery pack is my goal. Hook me up! Teach me something.

 

[Hashime]

This is what I am thinking, SCH 80 pipe and fittings, some old NiCad batteries, and 3 powerful LED lamps, as for the lamps I have no idea.
For Voltage regulation my cousin is going to make an induction circuit or something like that for me to keep it efficient.

 

[AnAppleSnail]

This is what I am thinking, SCH 80 pipe and fittings, some old NiCad batteries, and 3 powerful LED lamps, as for the lamps I have no idea.
For Voltage regulation my cousin is going to make an induction circuit or something like that for me to keep it efficient.

Important note: With LEDs you want to regulate current, not voltage. LEDs have a characteristic called 'forward voltage.' It changes with the current you drive them at - an LED driven at 0.1 volts higher is going to have quite a lot more current going through it. The Vf of individual LEDs is not the same at a given current - it centers around a range for each input current. They are very sensitive to their individual Vf and changes in that output voltage. LED drivers are commonly available in different and multimode outputs, and they aren't too ugly to build either.

I'm no diver, but there's one thing I've learned in messing with my flashlights while swimming - throw is king. If you aren't in beautiful tropic glass-water you'll want either a big reflector or throw optics. Optics are popular, either for efficiency or the output patterns they make. Aspherics are the best throw - you lose lumens, but then you'll only have lumens where you want them, not blinding you. If you don't build a light with throw, you'll get a wall of lit cloudiness in front of you that'll ruin your light's ability to...well, light.

Most optics or reflectors just want the right sort of LED placed appropriately and you get the advertised pattern - like a 5 degree optic will make a cone of output with half intensity at the 5 degree point. That is, inside that cone it's brighter than half intensity, outside it's dimmer than half intensity. Aspherics can be tightly focused and have almost no output outside their output cone.

 

[Hashime]

Important note: With LEDs you want to regulate current, not voltage. LEDs have a characteristic called 'forward voltage.' It changes with the current you drive them at - an LED driven at 0.1 volts higher is going to have quite a lot more current going through it. The Vf of individual LEDs is not the same at a given current - it centers around a range for each input current. They are very sensitive to their individual Vf and changes in that output voltage. LED drivers are commonly available in different and multimode outputs, and they aren't too ugly to build either.

I'm no diver, but there's one thing I've learned in messing with my flashlights while swimming - throw is king. If you aren't in beautiful tropic glass-water you'll want either a big reflector or throw optics. Optics are popular, either for efficiency or the output patterns they make. Aspherics are the best throw - you lose lumens, but then you'll only have lumens where you want them, not blinding you. If you don't build a light with throw, you'll get a wall of lit cloudiness in front of you that'll ruin your light's ability to...well, light.

Most optics or reflectors just want the right sort of LED placed appropriately and you get the advertised pattern - like a 5 degree optic will make a cone of output with half intensity at the 5 degree point. That is, inside that cone it's brighter than half intensity, outside it's dimmer than half intensity. Aspherics can be tightly focused and have almost no output outside their output cone.

So just using the LED's natural directionality will not work?
If so, switching to a canister design does not change must in terms of the supplies I already have. I designed this light around what is available for free to me right now. If I can make the single piece style work, I save a lot of money.
My cousin is also quite handy with electronics (as am I to an extent), so the actual powering of the lamps will not be an issue, but thanks for the advice anyhow, I at least learned something.
Last question, are there LED lamps available that would cut out the need for a lens/reflector?

 

[jspeybro]

So just using the LED's natural directionality will not work?

most likely not, unless you're designing a video light. Are you talking simple 3 or 5mm leds, or high power leds. High power leds are the way to go.
For a dive light, you'll probably want something with a angle <20° (don't be fooled by the datasheets of optics, sometimes they mention the half angle or note it by ±5° which is actually 10°)

If so, switching to a canister design does not change must in terms of the supplies I already have. I designed this light around what is available for free to me right now. If I can make the single piece style work, I save a lot of money.
My cousin is also quite handy with electronics (as am I to an extent), so the actual powering of the lamps will not be an issue, but thanks for the advice anyhow, I at least learned something.
Last question, are there LED lamps available that would cut out the need for a lens/reflector?

you could use so called drop-in modules. There are plenty available at kaidomain.com and dealextreme.com.

but as mentionned earlier, learn to dive first, then make a light. maybe hire a light once to see the result of the leds and optics.

 

[H20doctor]

i have made lights with threaded caps back in the day , and even with pipe sealer on the threads with teflon tape... it leaks .. so the thread wont work ... But you can use a good Oring style with canister latches.. Good luck and keep building

 

[Klem]

Hashime,

Where does the O ring go on your 80mm pipe fittings? Your diagram does not show the waterproof sealing method, and this is critical.

I agree with the Doctor; for a seal that needs to be regularly opened (e.g. for battery charging) thread alone is insufficient.

 

[Packhorse]

I used a threaded lid on a PVC pipe cannister for a number of years and it sealed very well. Of course it used an Oring but it was the stock Oring that came with the PVC threaded cap.

In fact I was using this system up until a few months ago when I sold it.
The new owner recently informed me he flooded it but I believe he didnt tighten it up properly. But due to the "dry lid" design the batteries remained dry and at worst he may have ruined the relay.

So dont let people tell you it cant be done. It can be and it can be done with some very simple tools.

BUT its not the best way to do it.

 

[Klem]

So we are agreed then..."thread alone is insufficient."

I too have used threads with O rings...but threads without an O ring or silicone bar of some sort is insufficient.

I am interested in Hashime's seal concept. Is it an O ring that seals by mating at right angles as it tightens (the most likely to leak), or is it a friction fit that rubs along the sides of the other surface as it tightens (like the end cap of a Maglite)

 

[Linger]

Hashime, I suggest you read up, there's lots of great posts here showing some unique builds.
This is a modification
http://www.candlepowerforums.com/vb/showthread.php?t=249291

This is a custom
http://www.candlepowerforums.com/vb/showthread.php?t=278901

I'd suggest shelving all design ideas until you get a working bench-top light. Your questions are just way to basic to progress all the way to finished dive light with one prototype. AND ... you'd want a 'new custom' light as a new diver? Way too much task loading. Buy a decent light (used) for the beginning.

 

[Hashime]

Yes, there is an O-ring in the threaded cap. I was also thinking I could use a Silicone "cup" or an insert that fit over the whole diameter of the pipe and was squeezed down into position.
As for the LEDs I want to use high power lamps that will light up a small area, I don't want to take video or pictures with this light, just see my gauges well and be able to illuminate say a wreck that is about 3-4 metres away from me if the visibility allows.
I want to make something quick and dirty.
As for the learning to dive thing, there are 4 dives during my open water weekend, the last 2 are purely for pleasure, I was planning to take the light on them.

 

[Hashime]

Hashime, I suggest you read up, there's lots of great posts here showing some unique builds.
This is a modification
http://www.candlepowerforums.com/vb/showthread.php?t=249291

This is a custom
http://www.candlepowerforums.com/vb/showthread.php?t=278901

I'd suggest shelving all design ideas until you get a working bench-top light. Your questions are just way to basic to progress all the way to finished dive light with one prototype. AND ... you'd want a 'new custom' light as a new diver? Way too much task loading. Buy a decent light (used) for the beginning.

I know that my questions are basic, but I want to keep it basic, I don't need adjustable lenses or anything fancy, basically I just need a recommendation on what LED lamps to use for the best underwater general lighting, I plan on figuring the rest out myself for the experience.
Thanks.

 

[350xfire]

I know that my questions are basic, but I want to keep it basic, I don't need adjustable lenses or anything fancy, basically I just need a recommendation on what LED lamps to use for the best underwater general lighting, I plan on figuring the rest out myself for the experience.
Thanks.

OK, so Maglite head, DX 5-led set up, PVC canister... LiIon batteries.

Or just buy an Intova LED light for $70 and be done with it!

 

[Hashime]

Thank, that sounds like a good plan.