Long distance wide beam IR

[LukePerry085]

Hello all, first of all let me applogize if I have posted in the wrong section, as this is my first post. I have been researching building my own long distance night vision (looking for something that will reach out to no less than 100yds, preferably more in the range of 300yds - the wider the view the better). I'm not terribly worried about it being eye safe, as I don't plan to ever employ it in an urban environment (I would like to use it for predator hunting - something that is legal at night in my state). I am very experienced in the various realms of electronics and mechanics, so repackaging digital camera internals into an eye apparatus (or preferably a dual eye apparatus) should be quite easy for me. This however leaves me with the choice of the IR light source that I will use.

When first tossing around ideas in my head I decided that normal IR LEDs would be insufficient for much more than lighting a large room, which lead me to think that an defocused IR laser would be my best bet. So here I am wondering what the best source is. I have read that CD writers generally have an IR laser diode in the 60mw range (I have since gutted 3 spare ones here at work and have been playing with them a bit), but then I have to source optics as well and good optics are not cheap, especially when you don't know exactly what you need, not to mention the fact that I'm not sure if 60mw is bright enough for what i'm trying to do. The other obvious option would be to get an IR laser pointer with an adjustable lens, which would offer several advantages: possibly brighter than 60mw, built in optics, built in driver. I do not know, however, if the built in optics would even spread the beam to the width that I'm looking for.

Any recommendations?

 

[DrSid]

You can get some real cheap IR pointers with adjustable focus. Check this site:

808nm 220mW laser torch /adjustable/burning [OL808-200] - $39.00 : Zen Cart!, The Art of E-commerce

I don't have night vision, but AFAIK 200mW is way too strong. But with this price you can get idea about power needed. Also it's likely you would be able to use the optics at least for any weaker laser if needed.

Be warned though. IR lasers are dangerous, as the light is invisible. If it will be defocused, it would be fine, especially at distance, but it still be dangerous, especially to you, during experimenting, mounting and so on. It might also be strong enough to damage your night vision equipment with direct hit or reflection of glass/metal.

 

[LukePerry085]

Thanks for the link. I ordered that, now we'll see how it works for my needs. Thanks also for the IR laser safety warning, something that I have read about and will treat with the utmost of care.

I was reading an article that somebody was doing something similar to what I am (except that it was for camera use) and found that using a laser of similar mW rating with an adjustable lense he was able to get a 10ft spread at 50 ft of distance. It seems to me that this would be a linear scale, so I should see a 60ft spread at 100yds if my logic is correct. This was not enough for him, who was looking for a long distance flood light, but I think that may be very sufficient for my requirements, as something a bit more like a spotlight may be okay. If not, I can do optical tuning like he did, which is what was able to get him the shown spread at 100ft:

 

[LukePerry085]

Well I received the 220mW laser that was linked in the above post today, and I went and bought a brand new pair of Duracell lithium batteries for testing and it won't even cast significant light across the street when viewed through my cell phone camera (I have verified that this views IR), unless it's adjusted down into a fine dot. Either 220mW is WAY too dim, or it has a diode with a LOT less power than advertised, or my cell camera doesn't view enough of the IR spectrum.

 

[lasersbee]

Do some under closer tests with the Laser Beam and Camera..
then scale up to "across the street"...

And wear some appropriate Laser Safety Goggles/Glasses
when using your High Powered IR Laser...


Jerry

You can contact us at any time on our Website: J.BAUER Electronics

 

[DrSid]

Well I received the 220mW laser that was linked in the above post today, and I went and bought a brand new pair of Duracell lithium batteries for testing and it won't even cast significant light across the street when viewed through my cell phone camera (I have verified that this views IR), unless it's adjusted down into a fine dot. Either 220mW is WAY too dim, or it has a diode with a LOT less power than advertised, or my cell camera doesn't view enough of the IR spectrum.

Well cellphone cameras, as most cameras, have IR filter built in them. This can be removed. It's pretty tricky in a cellphone though. It's much easier in most webcams though. Try buying some cheap one and dismantle it. IR filter is green looking glass glued either to optics or to sensor.

 

[Blord]

Well I received the 220mW laser that was linked in the above post today, and I went and bought a brand new pair of Duracell lithium batteries for testing and it won't even cast significant light across the street when viewed through my cell phone camera (I have verified that this views IR), unless it's adjusted down into a fine dot. Either 220mW is WAY too dim, or it has a diode with a LOT less power than advertised, or my cell camera doesn't view enough of the IR spectrum.

What do you expect ? 220mW IR is still 220mW of power. Imagine a high-power LED at this power. To cast something visible across the street you need tens of Watt of LED power. 220mW is nothing.

 

[ryansoh3]

I'd recommend a HID flashlight of 50-80 Watts on ebay or a high powered halogen and stick an IR cover over the head. The filter should only allow IR to pass.

 

[Atomicrox]

Visibility varies a lot from camera to camera. My iPhone barely picks my IR laser but my aunts low end Nikon picks it up very well. It's also easy to remove the IR filter on a camera. I've never done it but should improve visibility substantially.

That picture of the house seems very well spread for an IR laser. They're usually multimode and provide very ugly and irregular "dots".

Also note that 808nm isn't invisible, you should be able to see the focused dot from your laser on a surface a couple centimeters away. Don't stare at it! Not sure how well animals will see it but they just might.

 

[DrSid]

Actually I expected you will use dedicated night vision goggles with the laser. They are quite sensitive to these wavelengths.

 

[Fiddy]

hey man,

you could always use a 1W 9mm diode, they have horrible divergence, which is good at covering larger areas!

heres a video of mine:

 

[armalite]

here take a look .. long range NV security cam

they use 808nm , output power 15W