Since i want to build a IR illuminator for some distancen for use with a NV setup, i started small. VERY small and very slow. Initial results are very encouraging. Rather than go hoq wild and half cocked, i wanted to test waters in the shallows, and also, numerous well intentioned hints to start with a visible laser finally made a spot of sense.
namely, to make a teensy first build with a cheap, 5mW (if even that) visible red unit, because it being visible makes it very easy to fiiddle, fidget, and "play" with it. Obviously the low power visible red makes it extremely safe to start out with as well. I can "scale up" later. YET, the initial tests were very satisfying.
1) i have a cheapie "maybe 5mW" red visible DOT unit, its the sort of cheap thing sold at WalMart, with a bracket to plop onto a bbgun or 22. It holds a smallish flashlight and a baby red dot laser. I mounted the visible red aiming dot laser more or less where and how the IR illuminator will finally go. Since this unit has X and Y aiming screws, its easy to play with as well as being visible.
2) I wantd to see what a "laser illumination" looked like on the black and white security cam display, focused thru a low end rifle scope.
I already found several lenses that enlarge the RED DOT and make it much larger on the wall feet away. I selected one that makes a couple inch DOT at a couple yards across the room. it encircles a pack of smokes at that range. Its naturally a horrible large red dot, composed of little sparkling red dots. Viewed thru the security cam running in night mode (black and white) and thru the rifle scope? Actually, all things considered, not TOO shabby.
on 3x, the circle of illumination is a little smaller than the field of view, but, by 9x the field of view is noticable smaller. The BEAM iitself, when cigarette smoke is blown on it? it NOT hitting a focal point then crossing over and going out from there. It is starting tiny and spreading out in what appears to be a couple/several degree CONE.
this "uncollimation" of the tight beam is precisely what i need for illumination purposes, and moreover, the degree of divergence appears at first initial blush, to be a good "fit" for the field o view of the scope. Most of the FOV useable at 3 power, and on 9 power (zoomed in) more than covers the whole FOV.
I hate to ASSUME anythign at all, but, my initial assumption is that i have the couple/several degrees divergence i want and need. My assumption is that at a longer distance, the field of view(s) of the rifle scope is from 3 to 13 degrees roughly, and that this degree of divergence should stay proportionally sized inside/over the field of view at differing distances?
the scope and laser START within inches of each other, and the degrees are close, FOV vs laser-divergence...
========================================================
this leads me to suspect that i can now quite simply replace the 5mW visible red laser with a IR DOT MODULE (of suitably increased power) and expect more or less same/similar results.
this setup "works" out to less than 10 yards (about 7 is pushing it) but this is only a 5mw or less laser dot being bumped up by the lens. My hypothesis is that the IR DOT should worrk as a higher powered replacement, and i know that the beam is NOT a collimated tiny spot which would be more dangerous, it is a divergent several degrees that should be less dangerous. (not that i will be careless with it)
there are any number of "losses" coming onto play here... i have salvaged lenses bumping the beam from tiny spot to large spot and setting up a divergence, they are by no means intended for laser focusing but seem to work on visible okay. (no reflections to me from them; i encased the lens by a sealed aluminum tube that closely matches the barrel of the laser unit. Its aluminum, so, any reflections go into the tube or out of it or back into the laser.
moving the laser to a LARGE spot makes it much less distance, not to mention the degree of divergece does its part as well. Not to mention, the RIFLE SCOPE limits the (reflected) IR illumination, and, the security cam runnign thru the rifle scope does the CMOS sensor no real good.
i know a more powerful IR dot will do BETTER, but, dont know the exact losses of any one particular loss, so definitely cant guess as to what the overall combined losses will be, and cant guess ahat power will be required to go what distance.
=======================================================
but for a test "shallow kiddie pool" run? I call it a blazing success. Actually, the 5 yard image? it sort of resembles what you get when a safety window takes a hit from a baseball? a circular, ringy, slight "cracked ice" sort of view. Hardly great IMAGE quality.... but... it works and it works WELL.
i just wonder idly how much distance improvement i get when i shift to a 250, 350, or maybe 450 mW powered "ir dot module". The "bonus" will not be only power, the dot size should have some bigger smaller focus adjustment, which might (i hope) allow me too tailer the size of the projected beam (which is already close) to the 3x field of view. Jut a HAIR bump up in size will allow my "mm to inches" sized dot to perfectly fit the degree field of view.
on the assumption that if the degree of divergence fills a certain amount of the field of view at ONE range, it should proportionally fill the same field of view at distance?
=====================================================
image quality is more than acceptable for a rifle scope view, given seeing in complete darkness.
any educated guesses, what 5mW bumped up to any larger power, and given the shoft from visible red to IR (either 808 or 830-850) might be in terms of distance?
guesing somewhere around 7 yards max now, before its too dim to see... but i really didnt expect much from 5mW anyways in terms of distance. I'm actually pretty excited this test went so well.
namely, to make a teensy first build with a cheap, 5mW (if even that) visible red unit, because it being visible makes it very easy to fiiddle, fidget, and "play" with it. Obviously the low power visible red makes it extremely safe to start out with as well. I can "scale up" later. YET, the initial tests were very satisfying.
1) i have a cheapie "maybe 5mW" red visible DOT unit, its the sort of cheap thing sold at WalMart, with a bracket to plop onto a bbgun or 22. It holds a smallish flashlight and a baby red dot laser. I mounted the visible red aiming dot laser more or less where and how the IR illuminator will finally go. Since this unit has X and Y aiming screws, its easy to play with as well as being visible.
2) I wantd to see what a "laser illumination" looked like on the black and white security cam display, focused thru a low end rifle scope.
I already found several lenses that enlarge the RED DOT and make it much larger on the wall feet away. I selected one that makes a couple inch DOT at a couple yards across the room. it encircles a pack of smokes at that range. Its naturally a horrible large red dot, composed of little sparkling red dots. Viewed thru the security cam running in night mode (black and white) and thru the rifle scope? Actually, all things considered, not TOO shabby.
on 3x, the circle of illumination is a little smaller than the field of view, but, by 9x the field of view is noticable smaller. The BEAM iitself, when cigarette smoke is blown on it? it NOT hitting a focal point then crossing over and going out from there. It is starting tiny and spreading out in what appears to be a couple/several degree CONE.
this "uncollimation" of the tight beam is precisely what i need for illumination purposes, and moreover, the degree of divergence appears at first initial blush, to be a good "fit" for the field o view of the scope. Most of the FOV useable at 3 power, and on 9 power (zoomed in) more than covers the whole FOV.
I hate to ASSUME anythign at all, but, my initial assumption is that i have the couple/several degrees divergence i want and need. My assumption is that at a longer distance, the field of view(s) of the rifle scope is from 3 to 13 degrees roughly, and that this degree of divergence should stay proportionally sized inside/over the field of view at differing distances?
the scope and laser START within inches of each other, and the degrees are close, FOV vs laser-divergence...
========================================================
this leads me to suspect that i can now quite simply replace the 5mW visible red laser with a IR DOT MODULE (of suitably increased power) and expect more or less same/similar results.
this setup "works" out to less than 10 yards (about 7 is pushing it) but this is only a 5mw or less laser dot being bumped up by the lens. My hypothesis is that the IR DOT should worrk as a higher powered replacement, and i know that the beam is NOT a collimated tiny spot which would be more dangerous, it is a divergent several degrees that should be less dangerous. (not that i will be careless with it)
there are any number of "losses" coming onto play here... i have salvaged lenses bumping the beam from tiny spot to large spot and setting up a divergence, they are by no means intended for laser focusing but seem to work on visible okay. (no reflections to me from them; i encased the lens by a sealed aluminum tube that closely matches the barrel of the laser unit. Its aluminum, so, any reflections go into the tube or out of it or back into the laser.
moving the laser to a LARGE spot makes it much less distance, not to mention the degree of divergece does its part as well. Not to mention, the RIFLE SCOPE limits the (reflected) IR illumination, and, the security cam runnign thru the rifle scope does the CMOS sensor no real good.
i know a more powerful IR dot will do BETTER, but, dont know the exact losses of any one particular loss, so definitely cant guess as to what the overall combined losses will be, and cant guess ahat power will be required to go what distance.
=======================================================
but for a test "shallow kiddie pool" run? I call it a blazing success. Actually, the 5 yard image? it sort of resembles what you get when a safety window takes a hit from a baseball? a circular, ringy, slight "cracked ice" sort of view. Hardly great IMAGE quality.... but... it works and it works WELL.
i just wonder idly how much distance improvement i get when i shift to a 250, 350, or maybe 450 mW powered "ir dot module". The "bonus" will not be only power, the dot size should have some bigger smaller focus adjustment, which might (i hope) allow me too tailer the size of the projected beam (which is already close) to the 3x field of view. Jut a HAIR bump up in size will allow my "mm to inches" sized dot to perfectly fit the degree field of view.
on the assumption that if the degree of divergence fills a certain amount of the field of view at ONE range, it should proportionally fill the same field of view at distance?
=====================================================
image quality is more than acceptable for a rifle scope view, given seeing in complete darkness.
any educated guesses, what 5mW bumped up to any larger power, and given the shoft from visible red to IR (either 808 or 830-850) might be in terms of distance?
guesing somewhere around 7 yards max now, before its too dim to see... but i really didnt expect much from 5mW anyways in terms of distance. I'm actually pretty excited this test went so well.
