Laser for a Specific Application

[Reefer]

So I've been reading about different options, but I'm a little unsure about what is really needed. I will be burning pests inside a saltwater fish tank, up to a distance of 2 feet through the glass. It will have no other purpose and will only be used inside with no one around. I have read about some people using the 1W cheap premade models that seem to do the trick if the focus is just right.

I'm looking for a cheap option, I can DIY it if necessary. I have a lot of electronics experience and an expensive digital iron, no experience with lasers though. Does not have to be a portable pen, I am fine with a DIY enclosure and a DC wall plug.

No color preference(no IR). Can someone recommend a good option for me? Which wavelength, power rating, driver, etc...? Basically it will need to superheat soft tissue as well as small hard shells to boil what is inside. All of this through glass into water, up to 2 feet from the target.

Also, I have read about the glasses necessary, but I have also seen talk about IR leakage? and the glasses not being totally effective. Could you also recommend a pair of glasses to match the laser? I'd like to keep my eyes in perfect working order if possible.

Thanks!

 

[PersonGuyDude]

Wow there's a first for everything.
Blue is cheap for the power (1-2W), but violet is the best visible wavelength as far as burning power per mW goes. IR leakage only occurs with green or other dpss lasers, which would not be cost effective for your application.
Ill let the pros recommend the rest.

 

[Ablaze]

If you're looking for burning you'll want to make sure you select a focusable laser. Look for a high powered 405nm near 1w if you want the best price.

You already know this, but I'm gonna say again: Buy protective glasses with the laser.

 

[Ash]

You probably want to use True Blue 445nm, as violet (ie:bluray) 405nm is much too dim to see and use effectively for burning fish parasites. :thinking:
Also a 1W bluray will cost over twice what a 1W true blue laser costs.
Garoq has some nice easy "kits" to build your own portable 1W 445nm laser at Survival for about $200. If you didn't want to build it yourself, you could probably find a ~1W blue in the b/s/t section here for less than $150.
Or, you could just get a labby (plug-in) module that wouldn't have any duty cycle. o-like
Side note: Have you tried the normal parasite killing stuff they sell at the fish store? It will probably take a really long time to kill them with a laser, and the threat of back-reflections from a 1W laser off the fishtank glass (even with safety glasses on) would make me think twice before attempting it.

 

[HaloBlu]

I haven't seen any laser goggles for fishies.. But I bet you could create them, convincing fishie to keep them on might be hard tho. :san:

Reflections / accidents could damage the vision of fish. If your careful it might be ok but it will be a risk.
If you go DIY or buy off the forum personally I would go for higher then 1W. The 445nm diodes can take a bit more often.
http://laserpointerforums.com/f39/fs-aurora-c6-kits-68348.html#post985722 Mohrenberg has the least expensive 'Just Add Diode kit' I've seen. You can ask for a different power as well. Options he has are here Mohgasm Linear Drivers.
Since Moh has been here its never been less expensive or easier IMO. http://laserpointerforums.com/f51/aurora-c6-group-buy-tutorial-67080.html

Oh yea. Welcome to LPF.
Hopefully your show us what you wind up doing for the fishies.

 

[Ghostchrome]

What kind of pests are we talking about here? It's a pretty exotic solution, but gees, there's got to be a cheaper and less dangerous way to do something like this.

 

[Ash]

http://laserpointerforums.com/f39/fs-aurora-c6-kits-68348.html#post985722 Mohrenberg has the least expensive 'Just Add Diode kit' I've seen. You can ask for a different power as well. ..

This is good advice. With one of moh's kits set to 1500mA, you could make a relatively powerful burning laser for less than $80.
Remember, with a diode driven at 1.5A in a handheld, the duty cycle (run time) will be limited compared to a lab laser. So you can only use it for a few minutes before having to let it cool down for a bit. :undecided:

 

[Reefer]

Thanks for the replies guys, I've been doing a lot of reading and I think a lab style is probably the best bet given the amount of time this will take. We've had the same concerns about the fish possibly being blinded, I'm considering a piece of black acrylic in the tank as a semi-divider.

As for why the laser, there are no medications or any other means to remove this pest. They are small snails that grow on the rocks and grow to plague proportions.

Probably going to start with a 200-300mW red laser to get familiar with this. I'll definitely check out the 1.5W kits afterwards. Going to grab the OEM or Eagle glasses.

Don't worry, I'll post video.

Oh, one thing I was wondering about is the lenses, maybe I'm not finding the info. I've seen the acrylic lenses, glass lenses, and the g2 lenses. I'm guessing the acrylic lens is good for a certain power, then you go to glass. Is the g2 lens worth the extra money over a regular glass? That also brings up something else we were wondering about. Will the higher power lasers like 1-1.5w affect the glass of the tank in any way? What about an acrylic tank?

Thanks!

 

[Reefer]

Found all the info after talking with DTR. Went ahead and ordered a 445nm diode/module with glass lens and a flexdrive at 1500mA. Decided to use the flexdrive to avoid ordering parts from mouser and to save time for now, plus I don't want to blow this $43 diode.

Going to be drilling a P4 heatsink/fan with a 15/32 bit on my press. I'll probably fill the tiny gap with aluminum foil and thermal paste. I'm guessing this setup should put me around 1.5W, possibly a little over?

Also ordered 2 pairs of the eagle combo wavelength glasses from survival laser.

What are you guys using as a target surface for bench testing? I'm guessing I don't want a 1.5W laser pointing at my wall...

 

[HaloBlu]

For a target surface, anything that won't burn & has a flat non-reflective surface. Brick, back of a ceramic tile, non-reflective metal, stone. A block of wood if you don't mind some smoke. Professional target surface is called a beam stop.

Whatever your diver is set at you will be getting a bit less as optical power since some power is lost as heat in the diode. The exact amount of optical power depends on how efficient you particular 445nm diode is. I believe 1.25A gives at least 1W from even inefficient diodes.?

These 445nm diodes are pretty resilient as long as you don't really push it. People use cheap flashlight drivers sometimes that you wouldn't want to trust with other diodes.
Did DTR say a flexdrive can do 1500mA? I feel like I recall that being more then they can really do. Shouldn't hurt the diode, it just may not reach 1500mA even if set for that. If I recall that was one main reason people started making linear drivers, they can do more (with a heatsink on it). Its also cheaper.

 

[Reefer]

I'm not sure about the flexdrive at 1500mA. I guess I can throw my meter on it and find out. The main reason I got the flexdrive was to avoid killing the diode on my first attempt. I was going to keep it and adjust it down to 1W or so for a handheld later. Maybe even down to 500mA for a handheld red. Once I do some more reading and testing I will probably switch to a DIY driver since its a lab style. Then again, I do have a fair amount of electronics experience, it would just really suck to throw away $40 on my first try.

 

[Reefer]

Thought I would post the video of my test tonight, figured you guys would want to see. Headed to bed, will grab some pics of the laser setup tomorrow.

 

[Nocturnal]

wow!
does it work as well as you thought it would?

 

[Reefer]

Well, seeing as I didn't have a reference to go by being new to lasers. I was thoroughly surprised by how powerful it is. As you can see it burns pretty quickly. I also tried it on some small pest snails and within 2 seconds they popped out of their shells.

 

[Ash]

Wow. Really neat video.
Thanks for showing us exactly what you're doing. +Rep.
Question though: Are you killing the little stationary animals that look like they are "fanning" the water for nutrients? And, if so, are they bad for your marine environment in some way? :thinking:

 

[Reefer]

Thanks! I'm only killing the brown hollow looking tubes as they spread everywhere and sting everything. Everything else in the tank is unharmed.