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A Unique Use for Lasers

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Hey Guys,

Long time stalker, first time poster. I have an idea for a build, but I'm definitely going to need some help. First, let me give you the back story.

I am interested in hunting hogs (wild pigs) here in Texas. An interesting fact about them is they lack the cone cells needed to see red light and thus are much less sensitive to red light above 650nm. If you use a filtered white light it usually has too much spill into their visible spectrum and they run off before you can shoot.

So here's my idea. Can I build or buy a laser that has high enough divergence to create a pure red 650-660nm red 'spotlight' that could be scope mounted for hogs? I strongly suspect they will be able to see a faint glow if the intensity is high enough, but with a widely diverged beam or diffraction cap I don't think they will be able to see it.

I was thinking about possibly using a plain old 200mW 650nm with a focusable lens, but how big can you get the spot on these at 100yds (or 100m)? Can anyone with one chime in on their experiences using it as a laser spotlight?

Thanks guys, this is a fascinating hobby and I can already feel myself getting sucked in!

~Picksmither
 

AJ_Dual

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It'll be as big as you want. Most any laser with an adjustable focusing lens will make a spot as wide as a flashlight.
 
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You're best bet would be one of those 500mw 635nm diodes. They're much brighter and as a result you'd be able to cover a wider area.

If you really only need 650 or above you can just buy a 300mw from lazeer and it is focusable to a spot.
 
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See the problem is that I need the minimum brightness to clearly discern the hogs without getting so bright they can see it too. I imagine it is like us and 750nm diodes, you can still see it, but it is significantly more dim compared to a 650.

So do y'all think a 650nm 200mW at 100yds would actually be bright enough to see something if the spot is say 6ft round? If so, why hasn't anyone else done this?
 

jmiraval

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great idea for a practical use of a portable laser. i was pondering one day about home protection using a high power laser. with home intrusion here in florida (much like texas) you shoot first then ask questions. so the idea of blinding a malitious intruder with a high power burst of laser light would be less dangerious to other persons and not life threatening to the intruder. plus with a laser, that whole hitting what you are aiming at is brought to a whole new level.

oh and no i don't think at 100yds it would be effective. red is already hard enough to see and with the amount of light you would need to put downrange... it would probably over expose your eye to where you woulnt want to look at it anyways. but it would be quite the expirment to document.......
 
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jmiraval

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another thought is that with coherent light, no so sure you would be able to make out objects......
 
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I put a lens over my 100mw green and use it as a flashlight and I can make out objects just fine in the dark provided they have some different colors that gives green contrast I.e red is black green and green is just very bright green. You may want to consider a IR laser diode and a night vision imaging system instead. You can make them cheap from high powered IR laser diodes and a old digital camera with the IR filter removed. This will allow you to see 1 W of IR light up the area, which would be waaaaaay brighter than a 200mw red.
 
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I like this idea! Although, I don't know how bright a 200-300mW 650nm laser would be at 100m. I would imagine it would be pretty dim, but if you are looking at the illuminated area through a scope, it might work just fine. You could also have one built with multiple diodes (LPCs are cheap) to illuminate the area, alignment wouldn't be too much of an issue for unfocused beams.

Before you put the money into having one built, you might want to test whether a hog can actually see the light or not. They are pretty easy to spook (at least the ones around CA), and would probably run off if they could see it AT ALL.
 
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The other problems is that hogs are black and that probably won't give me much contrast with a red light. Do you think I would at least see silhouettes?

Ok, so with the laser that defocused it sounds like I wouldn't be able to see much at 100yds. Is that right?

What if I got a diffraction cap that produced the 'star' effect like this one: 660nm 200mW Red Laser Torch B03 [RF660-200mw-B03] - $42.99 : Rayfoss Lasers!, Rayfoss your trusable onlinestore
Would that provide me a pattern that I could make out objects at different depths maybe?

Also, would a diffuse pattern like that be eye safe at the long distances? Basically what I am asking is do I need to use glasses if it will always be pointing the same direction as a loaded gun (not at someone) and always outdoors.

I'm really thankful for the input so far, keep it coming!
 
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You'd be fine with it defoused at long distances. I just don't think one 200mw will be bright enough. Hell I couldn't make out details on a tree from 30 feet away with it focused like a spot.
 
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Here is a spectral sensitivity chart showing the sensitivity of the different cone cells. Basically hogs lack the 'L' or 'red' cone cells.



This is what I am hoping to take advantage of. IR is not off the table, but adds some complications and safety concerns.

@Dogs Best Friend : Sorry, what is an LPC? I searched for it but couldn't find the needed info.

@jmirival : home defense wouldn't be a bad use for this either. Hadn't thought of that. Though i think the courts might have some concerns about using such an unusual means to incapacitate a stranger.
 
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LPC-826 or LPC-815 diodes are the ones you will want to use for the build. They are the highest wavelength diodes that are still visible to human eyes. You can get them for around $10 ea.

You should also look around for 650-660nm LEDs rather than lasers. If the light is actually invisible to hogs, a red LED flashlight might be better than a laser.

I'm no hog physiologist, so I can't say exactly how this would apply to them, but opsin pigments can vary a lot. We call the different cones "red" and "green" because that's the peak absorption wavelength for the specific opsin they carry, but they are actually sensitive to a wide range of wavelengths.The "green" opsins in humans can detect a range of wavelengths that extends into the part of the spectrum we call red. It's possible that, even though pigs lack the "red" opsin, the absorption spectrum of the "green" opsins in pigs would extend far enough into the red to allow them to detect 660nm light.

I don't have a red laser right now, so I can't test it myself. If anyone has access to a 660nm laser and also a pig, I'd like to hear the results!:evil:
 
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PBK

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I have a Laser Genetics ND3 laser designator that is designed to mount on a scope for hunting. The optics are really good, and the focus is adjustable. The only problem is that it is 532nm. Maybe it would be possible to change the driver and diode to convert it to red. You can find them on ebay for around 120-150. Im sure one of the veteran members on here could help you out with such a build.
 

sinner

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If you are looking just for illumination, you should consider using a phlatlight RED which is crazy bright and will help to flood a wider area.. but i think it might scare them at close range..
 
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Hey, can someone with a 650nm 200mW open it up to a spot (3-6ft/1-2m round) at night and see how it does at distance?
 




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