True Waterproof Laser

I was messing around with an old SCUBA diving flashlight when I imagined fitting a small laser inside of it...

I took it apart and managed to fit a little 5mW red keychain pointer inside of it. I put it all back together and guess what? It's still waterproof! I haven't tested it at more than a couple of feet, but it definitely is waterproof at surface pressure. I suspect that it will hold pressure down to it's rated 100 meters, because I only took apart what I would take apart if I was replacing the batteries.
Only problem is that I haven't figured out a switch yet, I have to take the whole thing apart to turn it off. :/ Any suggestions?

I am planning on trying to fit a PHR-803T with a rckstr drive and a 9v inside soon... that is once my parts arrive In order to do this I will have to figure out some sort of switch, because while I can have a 5mW red shine for minutes on end, I'm not going to run my blu-ray indefinitely.

I'll take pictures once I have the final build, but thought I might get some thoughts flowing.

-Awlego

Here's a picture of the flashlight I used.

now you just need a way to make the case the heat sink and you could have water cooling for your blueray enabling really long run times.... well untill global warming happens or you manage to heat up the ocean : )

cool build tho.... did you think of a magnetic switch?

hmm. Interesting concept. Do you have any examples of magnetic switches? The case has a switch that moves a piece of metal on the inside, so I think I might be able to utilize that.

And as for the heat sink, I wish the flashlight was metal! That would be awesome! Somehow I don't think the heat will transfer from the normal heat sink to the plastic and then to the water very well though...

I guess I'll find out as soon as my parts arrive

-Awlego

Use a "reed" switch (you can find a lot of models, just be sure that you use one that carry the current that you need), and a little magnet ..... put the reed contact on one side of the case, and the little magnet in a plastic ring around the case ..... when you turn the ring, when the magnet is near enough to one of the sides of the reed contact, it close, when you turn it away, it open.

I use them for a lot of things, including underwater localization flashers (scuba emergency flashers)

What about just taking the wires coming from the built-in switch and making them part of the laser batteries circuit? simple and easy!

I suppose he wants both the laser and flashlight fucntion, but individually switchable. Something with a reed relay inside and a magnet outside seems the safest bet if you want to preserve waterproofing.

You could glue 2 pieces of metal on the inside, one with the reed relay behind it, and one without. An external magnet could then easily be slid from one piece to the other, and always be stuck to the case regardless of its position.

Thanks for all the advice! I'll take a look into both reed switches and making the normal switch part of the circuit once I have everything to fiddle around with. I'll post when I have built something.

if your using it for diving you might wanna pick a color more visable than 405nm. i would use green just cause the beam would be crazy bright and you probly could see the point and you can also get keychain greens that run off 1 AAA

Hey Awlego,

I have had the same thoughts about this build as you. My purpose for an underwater laser would be to mount it to my speargun for diving. I can't find any build on this site that uses any depth-rated host.

First off, I don't know your uses for the laser, but 5mW (especially red) ain't really going to produce a visible dot underwater in the daytime unless you are within 5' or even closer. You are going the right route by choosing blue. As kevin stated, green may be a better choice since it really stands out against a blue (ocean) background. Our eyes are able to spot bright green very well underwater. Here is a chart for absorption. This kind of shows how crappy a red laser would be. For distance, light blue in open ocean and green near the coast. For overall- my choice is green.

Note: The depth of the water doesn't matter, it is is distance from the laser to the object. My diving budies couldn't understand this because you don't see reds past 5'.




Those values in the first pic are Extremely overrated. This pic below is more accurate, and it shows 10% light that is left for each wavelength (the above pick must be .0001%light left).


To answer your question - the host you are using is similar to a light I have used for lobster diving in the keys. The switch may give you some problems contacting like mine did, but try and see. Some of my friends have used that light for years. For underwater use, the plastic housing shouldn't melt, but the lens may be plastic (like mine was). I am not sure how long lasting a high power laser would be going through it (leaving a burn mark?), but other people can answer that if it's plastic. These are some hosts I have looked at for this build.



-----Trident Underwater Laser Pointer at Divers-Supply.com




-----65502 Innovative Underwater Laser Pointer




-----UltraFire W200 200-Meter Waterproof Diver's Cree P4-WC 176-Lumen LED Flashlight (3*AA) [E13829] : BestOfferBuy.com, Buy DVD, Shop for PC accessories, Discount MP3 Players, Bargain Deal for Surveillance Equipment, Cheap R4 for NDS, X-sim Unlock




I'm not sure if this unit is rated or not. It says diving, then it says not waterproof?
-----Diving green laser underwater 100feet£*>5~200mw green laser pointer£*>Laser&lighting products£*>www.0-like.com




-----http://www.dealextreme.com/details.dx/sku.29069




This is my pick because of the clickey. It is quick and can be turned on with a finger instead of using both hands to rotate a bezel.
-----DealExtreme: $79.99 Aoxing 100M Waterproof Diving Cree P4-WC 3-Mode 150-Lumen LED Flashlight with Battery + Charger Kit




The bad thing with aluminum hosts is they will corrode. I don't care what alloy it is, it WILL corrode. Cleaning them after every use will greatly extend their useful lives. Plastic underwater dive lights are nice because they don't have to be cleaned every time (or ever). The only reason I haven't looked at large dive lights they would be kind of bulky on my speargun and in the way for my bands. I am thinking of side mounting it somewhere next to the trigger for quick on/off. Just FYI on lasers with fish, they sometimes freak out when they see one with some high mW's. So you don't want to put one on a jewfish or shark unless you want some real excitement underwater!



This build was how I found the laser pointer forum. -this is my first post, so hi everyone!

Really any 18650 tactical host would do, you just need a set of O-rings. But I don't see any way of getting around the switch problem, without wiring up a module...

@ kevinmassey

if your using it for diving you might wanna pick a color more visable than 405nm. i would use green just cause the beam would be crazy bright and you probly could see the point and you can also get keychain greens that run off 1 AAA

Click to expand...

Agreed. I would also pick something less than 110mA because I wouldn't want to dive wearing safety glasses either.

@ MECHANICal engineer

Hey Awlego,

I have had the same thoughts about this build as you. My purpose for an underwater laser would be to mount it to my speargun for diving. I can't find any build on this site that uses any depth-rated host.

First off, I don't know your uses for the laser, but 5mW (especially red) ain't really going to produce a visible dot underwater in the daytime unless you are within 5' or even closer. You are going the right route by choosing blue. As kevin stated, green may be a better choice since it really stands out against a blue (ocean) background. Our eyes are able to spot bright green very well underwater. Here is a chart for absorption. This kind of shows how crappy a red laser would be. For distance, light blue in open ocean and green near the coast. For overall- my choice is green.

Note: The depth of the water doesn't matter, it is is distance from the laser to the object. My diving budies couldn't understand this because you don't see reds past 5'.

Click to expand...

To answer your question - the host you are using is similar to a light I have used for lobster diving in the keys. The switch may give you some problems contacting like mine did, but try and see. Some of my friends have used that light for years. For underwater use, the plastic housing shouldn't melt, but the lens may be plastic (like mine was). I am not sure how long lasting a high power laser would be going through it (leaving a burn mark?), but other people can answer that if it's plastic. These are some hosts I have looked at for this build.

Click to expand...

Just FYI on lasers with fish, they sometimes freak out when they see one with some high mW's. So you don't want to put one on a jewfish or shark unless you want some real excitement underwater!

Click to expand...

If I was actually diving with it, I would try to use a green 5mW module. This is because, as you stated, green would be the most visible. I wouldn't want to used a high powered module for the sake of my eyes. I don't think safety glasses would fit under my scuba mask, and I doubt anyone makes a laser scuba mask. As for pointing at fish, I think this would be a bad idea... I follow the "look, but don't touch" diving philosophy That's different of course if you're fishing using it for a speargun.

Now that I've replied, I'll update my progress:
So while waiting for my blu-ray, I found a cheapo red laser in a drawer at my house and decided to take it apart. After extracting the diode, battery, and switch (no driver??? see note) I made a trip to Radioshack to buy a reed switch. They didn't have a reed switch, but they did have a reed relay, which is basically the same thing, only with a coil wrapped around it so the switch could be triggered electronically as well as physically.

I soldered the diode to the new switch and then attached the switch and the other side of the diode to the battery. The result is a laser that turns on whenever a magnet comes near the reed relay. I superglued a small neodymium magnet to the inside part of the physical switch on the dive light, so that it comes near the relay when I flip it to the "on" position. I put the flashlight all back together and voila! it worked! I promptly took a hot shower with lots of steam and tested my new waterproof laser. It worked great and even the far less than 5mW red beam was very visible in the steam.

My only complaint with the setup is that the beam power flickers. I believe that this has something to do with the reed relay. When I used a normal momentary switch to test my soldering connections, the power was stable. I think that, being a relay, it wasn't really designed to be used as a normal switch. Something is odd, but I can't really figure it out... sometimes the power is stable, other times it flickers. Whatever the case, it definitely turns on and off with the small magnet coming close to the switch, and as a proof of concept I am satisfied.

I plan on buying a true reed switch sometime soon and seeing how that works.

Also, I tried using various strengths of magnets, so it's having too much or too little magnetic force on the reed relay.

***Note***
This laser came with no driver. It uses a CR2032 battery, which according to wikipedia has a relatively low stable current. Is this just a bad design in a cheapo laser pointer, or are they using the special battery so they don't need a driver? Anyways, for the sake of my build, and since it's a cheap laser I don't care about, I will keep their circuit

If anybody wants pictures, let me know and take some when I get a chance. (though there won't be any of the beam as, while the laser is waterproof, the camera is not )

-Awlego