New Guy - Check Out My First Dive Light

Hi Everyone,

I've been meaning to post on CPF for a while now. Last year me and one of my friends made a pair of can lights for diving. The goal was to make a single light for under $100 in materials.

I've actually been using this thing for my last 30 dives and it has been working fairly well. That being said I want to design a new model with somewhat higher build quality. I am interested in learning a bit about aspheric lenses and different types of LED optics/cones in my next attempt. Any advice on slapping an aspheric lense on multiple LEDs would be appreciated.

Features:
- Triple P4 LEDs with polished aluminum reflector cone (Edit Note: 12 degree cone, actually used P4's not P7's)
- Homemade LED driver
- Therorectically Waterproof to 200', tested to 130' (used lots of JB Weld!).

Here are the pics of the first attempt:

Looks like you want the Homemade and Modified lights forum.

Welcome to CPF, DeNomad.

As Ray1968 suggests, I'm moving this to the H&M section. BST is for sales only.

Quite a battery tube

How many batteries are in there?

DeNomad said:

Any advice on slapping an aspheric lense on multiple LEDs would be appreciated.

Click to expand...

I'e found these lenses to be fantastic:
http://www.dealextreme.com/details.dx/sku.13903
They focus best when placed about 10mm from the LED. Achieving this can be a tad difficult, so I've discovered that modifying these makes it easy:
http://www.dealextreme.com/details.dx/sku.1920

What I do is first remove the clear prism from the white holder. Then I dremmell down the rim of the plastic holder. Check the height to leave, and if making multiple ones make sure they are all roughly the same height. Then smear some epoxy around the rim so that the lens is held in place and very gently move the lens slightly to get the beam coming out forwad.

This takes some practice, however it sure beats making holders and mounts from scratch.

I'm also building a dive light, I'm thinking of using 4x Cree R2 WG LEDs in the way I have just described. I have yet to find a good host for this. I don't want to make a can light, I'd prefer a lantern or pistol grip light. I also don't have the tools to make a host, so if you have any suggestions, please let me know

Good luck with it!

I see the pics, now.

That is one hell of a canister! Any underwater shots? Would probably make a great video light with 3x P7's.

Packhorse is the man when it comes to tight beam dive lights. Check out his 4x Q5 LED light here: http://sods.freeforums.org/here-we-go-again-t610.html

I'm a day or two away from having mine done which is very similar to his. I instead used a C sized maglite (gives more room in the head for a heatsink) and used CREE R2 LED's instead of the Q5's. Canister is made from Acrylic tube. Hopefully I'll have time this weekend to post pics and a part list.

LukeA said:

Quite a battery tube

Click to expand...

Oddjob said:

How many batteries are in there?

Click to expand...

Haha yea, there are 8x D batteries in that thing. It is actually quite negative so I can take a few pounds of lead off my weight belt.

The battery life is something like 15-25 hours, kinda forget what I originally calculated but it is a long time. I put the batteries in series because I read somewhere that putting batteries in parallel might load some LEDs more than others. I am not sure if that is true.... I'd like to cut the length of that canister in half by putting them in parallel next time.

DeNomad said:

I put the batteries in series because I read somewhere that putting batteries in parallel might load some LEDs more than others. I am not sure if that is true.... I'd like to cut the length of that canister in half by putting them in parallel next time.

Click to expand...

Putting the LEDs in parallel can cause the LEDs to receive unequal currents. The battery configuration doesn't have anything to do with that.

Running rechargeable cells is much cheaper than running alkalines after 10-15 cycles.

MrNaz said:

I'e found these lenses to be fantastic:
http://www.dealextreme.com/details.dx/sku.13903
They focus best when placed about 10mm from the LED. Achieving this can be a tad difficult, so I've discovered that modifying these makes it easy:
http://www.dealextreme.com/details.dx/sku.1920

Click to expand...

Thanks for the links. At that price might as well pick up a few to play with even if I don't use half of them.

MrNaz said:

I have yet to find a good host for this. I don't want to make a can light, I'd prefer a lantern or pistol grip light. I also don't have the tools to make a host, so if you have any suggestions, please let me know

Good luck with it!

Click to expand...

What do you mean by host? The only tools I used in making this light with the exception of two o-ring grooves were a hack saw, vice, hammer, cordless drill, and a dremel. I had to get a buddy to throw some bits on a lathe for the o-ring groove. If you want to know how I made something send me a PM.

heffay said:

That is one hell of a canister! Any underwater shots? Would probably make a great video light with 3x P7's.

Packhorse is the man when it comes to tight beam dive lights. Check out his 4x Q5 LED light here: http://sods.freeforums.org/here-we-go-again-t610.html

I'm a day or two away from having mine done which is very similar to his. I instead used a C sized maglite (gives more room in the head for a heatsink) and used CREE R2 LED's instead of the Q5's. Canister is made from Acrylic tube. Hopefully I'll have time this weekend to post pics and a part list.

Click to expand...

Thanks. Unfortunately no underwater shots as of yet. Need to convince one of my buddies to bring his video camera for a practice dive sometime for that.

It might do well as a video light, the cone has an 8 degree spread. The focus is still not tight enough for local lake dive conditions (dark and green). It is actually as bright as my buddies 21W HID but his HID has better throw/penetration/focus... whatever term you wanna call it lol.

Now Packhorse's light in that link is really impressive... I like very much!!

LukeA said:

Putting the LEDs in parallel can cause the LEDs to receive unequal currents. The battery configuration doesn't have anything to do with that.

Running rechargeable cells is much cheaper than running alkalines after 10-15 cycles.

Click to expand...

Your right, battery config doesn't have anything to do with that. Is putting the LEDs in parallel *really* that bad for them though?

DeNomad said:

What do you mean by host? The only tools I used in making this light with the exception of two o-ring grooves were a hack saw, vice, hammer, cordless drill, and a dremel. I had to get a buddy to throw some bits on a lathe for the o-ring groove. If you want to know how I made something send me a PM.

Click to expand...

I mean the head. Heat management is my biggest challenge. I want to put some high power LEDs in there, overdriven. The heat sink in the head would need to be in contact with the water, as I doubt the amount of power I intend to have in there will be able to be dissipated by the air.

I have toyed with the idea of using a Mag lite or something like this, but I don't have access to a lathe, so I can't make a heat sink inside that will actually contact the exterior.

I also have no idea about how to make a switch. I'd like a reed switch to eliminate the need for watertight penetrations into the body, but this is also an area I have no idea how to deal with.

I guess I need to read more peoples' build diaries to get ideas on these issues.

Ooh okay I getya now. My LEDs are mounted on an .25 inch aluminum plate. It will overheat when it is not used in the water.

It got switched on by accident in my car for 2 hours. It burned my hand and melted a electrical cord next to it.

I'd like to try a reed switch next time as well. There is a thread at TDS on it here:

http://thedecostop.com/forums/showthread.php?p=414835#post414835

Hope that helps. I'd like to design a reed-collar system that would "click" in the on/off position somehow. Don't want the thing to get brushed while diving and turn off.

DeNomad said:

Hope that helps. I'd like to design a reed-collar system that would "click" in the on/off position somehow. Don't want the thing to get brushed while diving and turn off.

Click to expand...

I've been toying with the idea of having no switch, and two electrical contacts very close to each other that are shorted when the light is in water. This way, the light will be always on when it is in the water, and never on when it is dry to prevent overheating while out of water.

It's a pretty wild idea, and part of me thinks "hey, that's not a bad idea" and part of me thinks "stop being ridiculous".

Thoughts?

MrNaz said:

I've been toying with the idea of having no switch, and two electrical contacts very close to each other that are shorted when the light is in water. This way, the light will be always on when it is in the water, and never on when it is dry to prevent overheating while out of water.

It's a pretty wild idea, and part of me thinks "hey, that's not a bad idea" and part of me thinks "stop being ridiculous".

Thoughts?

Click to expand...

Well it could work, many dive computers turn on in the water like that. I would be careful how much current you are jumping. If someone sticks their finger between the two contacts running 800-1000 mA...

Just be careful with that idea, maybe you could rig some sort of turn on circuit with low current/voltage. Maybe someone with more electrical background than me would know.

MrNaz said:

I've been toying with the idea of having no switch, and two electrical contacts very close to each other that are shorted when the light is in water. This way, the light will be always on when it is in the water, and never on when it is dry to prevent overheating while out of water.

It's a pretty wild idea, and part of me thinks "hey, that's not a bad idea" and part of me thinks "stop being ridiculous".

Thoughts?

Click to expand...

That's not a bad idea if you're using a single mode LED driver and don't need to "switch" from low to high beam or turn the light off underwater. The contacts would need to protrude thru the light handle I'm guessing? Which would involve cutting holes and sealing.

Whatever you employ, I'd ensure it can be overridden to allow signalling on the surface.

Good job! Satisfying building it yourself aye.


How are you getting 15-25 hours run time from 8 D's running 3 P7's?

I have 8 D 5ah cells and get 2 hours from 4 R2's!


You asked about multiple LEDs behind a single aspheric? Forget it. You will get multiple light beams and wyou cant align them.