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FrozenGate by Avery

Looking for a Pressure Safe Laser

Toaster

Toaster

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Ok, this might be taking it to the extreme but I am a diver and I am looking to perhaps have a laser that I can use underwater to attract sea life. (Yes it does work) Not to mention that I am sure it would look sick. I know there are water proof lasers, but does anyone know one that would be safe to use at depths in the pressures?

Thanks much!
 





Hmm, I think I could make one cheaper than that.. I just need to figure out how to water proof things. And the effects of pressures on things like that. you think a twist like a Maglite would be the best switch method?
 
Toaster said:
you think a twist like a Maglite would be the best switch method?
Click to expand...

Probably not.

You want a host with double O-ring seals.
A click on/off switch might be easier for one handed use anyway.

Some of the LED torch gurus probably will know what to look for.
It shouldn't cost much ($20-30) to have a nice custom aluminum heat-sink made for it.

What wavelength do you plan to use?
 
You might want to try a hall effect sensor which triggers a transistor for the switch.
"Arm" the laser before you submerge then turn it on using a magnet in your palm or finger.

This would allow you to make NO cuts or holes in the laser body and you would only have to seal the glass front and the rear battery input. Double Orings would be prudent on the aperture and the battery cap. If your power levels aren't too extreme... a polymer or acryllic exit lens would allow it to be bonded/glued watertight much more easily.
 
LazyBeam said:
You might want to try a hall effect sensor which triggers a transistor for the switch.
"Arm" the laser before you submerge then turn it on using a magnet in your palm or finger.

This would allow you to make NO cuts or holes in the laser body and you would only have to seal the glass front and the rear battery input. Double Orings would be prudent on the aperture and the battery cap. If your power levels aren't too extreme... a polymer or acryllic exit lens would allow it to be bonded/glued watertight much more easily.
Click to expand...

I was thinking of doing that a while back, I'd still like to give it a shot...

They are also called magnetic reed switches IIRC.
 
Hmm, Do you know if the O rings will hold to around 100m? Also, I have never even heard about that kind of switch. I will have to look it up.
 
I don't know how to go about rating o-rings, I would test the host before I filled it with anything to see if it will stay watertight to the desired depth.

I'm sure you've seen a reed switch before, those switches on doors and windows for burglar alarms are reed switches.
 
Yeah, I just wikipediaed it and I had a duh moment. Could that be operated in a stainless steel case though?
 
We use reed switches in some of our equipment and we have to drill a hole in the stainles for the switch the epoxy over it. The switch is inside of a 5/16 bolt (the head is cut off) about 3/4 of an inch long.

I will see i I can find a pictre of one and post it.
 
I think it would be much simpler to go with the basic clicky switch in the tail cap.
If it's needed, the silicone tail cap can be epoxied in place for a better seal.

Using a reed switch just adds more expense and custom work. Plus you will need to carry around a magnet if you ever want to use the laser.

This has double O-rings:
http://www.dealextreme.com/details.dx/sku.28545
But it's pretty tiny. You probably won't be able to fit a green inside easily. The window can be epoxied in place if necessary.

This one is a bit more substantial, looks better for more power:
http://www.dealextreme.com/details.dx/sku.32749
The large O-rings on the body can be done away with IMO.

I believe Jayrob and Flaminpyro make kits for this:
http://www.dealextreme.com/details.dx/sku.32563

Another:
http://www.dealextreme.com/details.dx/sku.23284

I don't see why any of these couldn't work.
 
Last edited:
I have a salt water tank and my fish prefer red! I think they can see it better especially my puffer. 650nm
 
Last edited:
Have you tried the greens and 445 and 405? Still red? What kind? 650 or 635
 
Toaster said:
What do you think would be the most visible in the water?
In Nm
Click to expand...

My friend has a fish tank.
They react to any color I have tried (405, 445, 532, 655).

Green will be the brightest, with 445nm close behind.
300mW of 655nm from an LOC will be pretty bright as well.
I would stick with green or red, since it will be attenuated less in the water.

UV doesn't penetrate water much (hence the beginning of life below the surface of the ocean) so I would think that evolution tuned fishy photo-receptors to favor longer wavelengths.
 
Last edited:
RA_pierce said:
My friend has a fish tank.
They react to any color I have tried (405, 445, 532, 655).

Green will be the brightest, with 445nm close behind.
300mW of 655nm from an LOC will be pretty bright as well.
I would stick with green or red, since it will be attenuated less in the water.

UV doesn't penetrate water much (hence the beginning of life below the surface of the ocean) so I would think that evolution tuned fishy photo-receptors to favor longer wavelengths.
Click to expand...

My puffer doesn't go after the green as much as my 405nm or the 650nm, I am afraid to try my 445nm, I don't want to blind one, if it it can.
 
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