Dive light project

steve6690 · Jan 25, 2008

Hi all,
it's been many years since I did any electronics but I'm thinking of having a try at building a Led dive light. Initially I want to sort the electronics out and probably try it in an old dive light. The plan then is to build an umbilical head and battery pack. I have no experience of led's and driver units though so I need to do some experimenting. I've been looking at DealExtreme to supply the bits. My initial thoughts are:

5 x Cree P4 on stars (sku 2134) driven at 700 ma from 5 x sku 3146.

I was thinking of mounting the stars on a circular copper plate with thermal compound and drilling holes for the wiring to pass through. I'm also planning to use tagged AA rechargeable batteries to make a 4.5V pack. The final product will need to give me around 4 hours of light before any dimming.
I need around 10 degrees beam so intend to play with various optics until I get something I'm happy with.

Am I way off with this plan or is it a reasonable start point ?

thanks for any help.

Steve

MatajumotorS · Jan 25, 2008

I need around 10 degrees beam so intend to play with various optics until I get something I'm happy with.

I have used NX05 optic with cree emitter, i think with good results, see picture - cree q2 @ 900mA, distance is 2,5m, baloon diameter is 10cm, ambient lighting is 23W fluorescent bulb.

steve6690 · Jan 25, 2008

That's a nice beam. I need something that cuts through the murk on UK wreck dives and that looks like it might do the trick

DM51 · Jan 26, 2008

Welcome to CPF, Steve. Interesting project.

You will find plenty of good advice here on the electronics of this, but it would probably be a help to show what you have in mind as the host to be used, so people can have an idea of what could fit inside it.

LukeA · Jan 26, 2008

steve6690 said:
Hi all,
it's been many years since I did any electronics but I'm thinking of having a try at building a Led dive light. Initially I want to sort the electronics out and probably try it in an old dive light. The plan then is to build an umbilical head and battery pack. I have no experience of led's and driver units though so I need to do some experimenting. I've been looking at DealExtreme to supply the bits. My initial thoughts are:

5 x Cree P4 on stars (sku 2134) driven at 700 ma from 5 x sku 3146.

I was thinking of mounting the stars on a circular copper plate with thermal compound and drilling holes for the wiring to pass through. I'm also planning to use tagged AA rechargeable batteries to make a 4.5V pack. The final product will need to give me around 4 hours of light before any dimming.
I need around 10 degrees beam so intend to play with various optics until I get something I'm happy with.

Am I way off with this plan or is it a reasonable start point ?

thanks for any help.

Steve

I like your driver setup. I would have recommended running at ~700mA. For beam-shaping, I like these 8-degree TIR optics from Kaidomain.

If you sand the white plastic holders down a little, you can fit 5 of those optics in a 2.25in. dia. circle.

steve6690 · Jan 26, 2008

Thanks DM51 & LukeA,

To be honest I have no idea what host will eventually be used. The final plan will be to design and build an umbilical head to hold the electronics but to start with I am hoping to get hold of an old canister light cheap, most likely one that uses 12V halogen MR16's, and use this to house it for underwater testing . I am aiming to make the package as small as possible so I intend to have the five reflectors practically touching. Obviously the final diameter of the assembly will depend on the diameter of the reflectors and it looks like I'll be ordering the ones from Kaidomain that LukeA suggests.

65535 · Jan 26, 2008

http://cutter.com.au/proddetail.php?prod=cut183

I would go with those optics personally, and use 3x Cree Xre emitters in either Q5 or R2 bin.

Amonra · Jan 26, 2008

Welcom fellow diver & CPFer

You may want to look at this thread: https://www.candlepowerforums.com/threads/186381
this thread: https://www.candlepowerforums.com/threads/180188
and maybe this thread: https://www.candlepowerforums.com/threads/117739

for some inspiration.

You want to stay away from plastic body hosts (at least for the head) as they will not allow effective thermal relief for the multiple led's. you will need a metal head and thermally connect the led heatsink to it.
This is the reason why many have used the mag heads, they are easily/cheaply available but a lot of work needs to be done to make them watertight.

LukeA · Jan 26, 2008

65535 said:
http://cutter.com.au/proddetail.php?prod=cut183

I would go with those optics personally, and use 3x Cree Xre emitters in either Q5 or R2 bin.

Those look like round optics simply cut to be hexagonal. Look at the machine marks on the flats. That will kill efficiency. Plus they're quite pricy.

In any case, the optics to which I linked are .919 in. in diameter, and .628 in maximum height when in the holders.

steve6690 · Jan 27, 2008

Lots of reading there for me :thinking:

to clarify though....I have a friend with a machine shop. He is also a PADI master instructor and he builds bespoke dive lights and camera housings. I'm going to see what he'd charge to machine a head from a solid alumini(u)m billet. I've seen some suitable stock lying around there so I know he has it. It's probably an hours work for him at most. The only tricky part might be machining the grooves for the double "o" rings which the glass front will sit on.
The plan is to machine a step into the body of the interior. I will then mount the emitter stars on a circular copper plate which will be fixed onto the step using screws and thermal paste. The drivers will mount to the back of the copper plate.
I'm thinking now though that it might be an idea to use a 12V system so I'd need to find suitable drivers. I don't like the idea of series connection for the led's for reasons of redundancy so I'd need 5 cheap drivers... possibly this

http://www.kaidomain.com/WEBUI/ProductDetail.aspx?TranID=2982

DM51 · Jan 27, 2008

Your friend with the machine shop sounds a useful guy to know!

He will need detailed drawings to work with, unless you leave the design up to him (but then it wouldn't be your creation, would it?)

Consider doing the drawings with a CAD program - that way you can amend them at will. A number of the custom builders here use CAD programs like that for their designs.

LukeA · Jan 27, 2008

steve6690 said:
Lots of reading there for me :thinking:

to clarify though....I have a friend with a machine shop. He is also a PADI master instructor and he builds bespoke dive lights and camera housings. I'm going to see what he'd charge to machine a head from a solid alumini(u)m billet. I've seen some suitable stock lying around there so I know he has it. It's probably an hours work for him at most. The only tricky part might be machining the grooves for the double "o" rings which the glass front will sit on.
The plan is to machine a step into the body of the interior. I will then mount the emitter stars on a circular copper plate which will be fixed onto the step using screws and thermal paste. The drivers will mount to the back of the copper plate.
I'm thinking now though that it might be an idea to use a 12V system so I'd need to find suitable drivers. I don't like the idea of series connection for the led's for reasons of redundancy so I'd need 5 cheap drivers... possibly this

http://www.kaidomain.com/WEBUI/ProductDetail.aspx?TranID=2982

Those are the drivers I would recommend, but I would only use 2, and I would pot the inductor coils in epoxy. Other than those inductor coils, there's not too much to go wrong. But it's your project, and I do know that I wouldn't want to be in the dark underwater. Still pot the coils in epoxy, though.

steve6690 · Jan 27, 2008

A CAD program sounds useful....I don't suppose there's such a thing as a free one is there ?

LukeA said:
Those are the drivers I would recommend, but I would only use 2, and I would pot the inductor coils in epoxy. Other than those inductor coils, there's not too much to go wrong. But it's your project, and I do know that I wouldn't want to be in the dark underwater. Still pot the coils in epoxy, though.

That's something I hadn't thought of... one driver to feed three in series and the other to feed two or did you mean something different ? How would I go about potting the coils in epoxy though, and what are the advantages of that approach ? thanks..

LukeA · Jan 27, 2008

steve6690 said:
That's something I hadn't thought of... one driver to feed three in series and the other to feed two or did you mean something different ? How would I go about potting the coils in epoxy though, and what are the advantages of that approach ? thanks..

I did mean 3 in series and two in series.

To pot the coils, just mix some thermal epoxy and coat the really fine copper wires and plastic piece that they wrap around with it.

The advantages of potting the coil are mainly to keep g-forces or contact from breaking either that tiny copper wire or the tiny plastic part that holds it up.

steve6690 · Jan 27, 2008

I like the idea of using two drivers. It gives a better balance of redundancy vs overcomplexity. I'll be sure to pot the coils too..

steve6690 · Jan 28, 2008

I've found a freebie CAD program to play with

http://www.free2design.org/index.php?option=com_content&task=view&id=21&Itemid=46

I just need to get to grips with it now...

steve6690 · Feb 12, 2008

Ok, a few changes to the original plan. I'm using 5 x Cree Q5 in series, driven by a MaxFlex. Phase one involves using a stock housing - the TG-1 - c/w with magnetic switch from here :

http://www.miemczyk-shop.de/

This is the same place that Mike from CPF sourced his housing for the 4 x Ostar dive light.

It actually works out cheaper than having my own custom housing made. Anyway, this way I can concentrate on the electronics and beam shape. One question I need to work out is whether a magnetic switch will function ok with the MaxFlex ie can it work as a momentary on/off switch for cycling through the various modes...

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