So far the most economical option I have found for cheap night vision would be to use an automotive backup camera with monitor, Amazon has them for $30 range with free shipping. The camera's should already have the IR filter removed because they come with IR LED light source.
On topic, machining required for camera mount to scope and monitor mount. The system is set up for 12V power and has cords for camera and monitor. These should be able to be powered by 3 lithium cells in series or other 12V power source. Add a good IR flashlight and optional IR laser sight for invisible night time shooting/pest control.
I think the flashlight/laser idea will be a disappointment: the flashlight won't illuminate well at long distances, and the laser will pretty much show you exactly where in the dark unknown your bullet will hit -- but you won't know if it's a legal-to-shoot varmint, or the neighborhood 5-year old.
For that matter, the IR that that camera sees is not the IR of thermal vision -- ordinary camera IR is about 1 micron wavelength; thermal vision IR is 3-5 micron or 8-12 micron.
Yeah, it takes a pretty good IR flashlight to see very far but some of them get out a few hundred yards. IR Illuminator testing
A guy with a camcorder siilar to mine setup on his scope for shooting rats.
I have a decent flashlight that came with rechargable batteries, scope mount, remote switch and pretty good lens to adjust from flood to beam. Feels weird being out in dark and only being able to see through the camera, holding camera in one hand and IR light in the other. My IR is 850nm wavelength and you can see the LED glow red but you can't see the light without the camera.
For those with some spare money the X-Sight digital day/night scope looks interesting. It combines the camera image with software for features such as one shot zero, has GPS and compass, accelerometer for tilt angles, recording video or snapping pictures, etc..
Why would it need an IR LED light source? You're only looking at it when the transmission is in reverse. (And at least on my Nissan Cube, the screen is only active when in reverse -- in forward or stop it is control of the entertainment system, or the GPS -- or both at once.
Granted, I would like to have it come on without having to switch into reverse occasionally. And I guess a third-party one would tend to be on full time -- easier wiring than having to tie into the back-up lights.
Now -- the cheap "security system" from Harbor Freight does have LED illumination -- for short distances, at least. One camera is under a solid piece of furniture where the cat hides during thunderstorms, and it is pretty dark there without the IR LEDs. But remember that the inverse square law says that there will be very little illumination as the distance increases. But it does a nice job of showing close snow during a storm at night. :-)
That Harbor Freight one is also powered by 12V -- with a wall wart as supplied.
If I knew that you had the money, I'd suggest you get a real thermal imager -- but a quick check shows a bunch of $300 ones that work with smart-phones, while the cheapest one that might make a decent scope starting at $1600 or so (and I have no idea what the authorities would think of a rifle-mounted thermal imager -- it'd be the bees knees for what you want, but the military likes them because they're a superb sniper weapon).
Imagine all the varmints lit up like torches in the darkness -- that's what things look like with a thermal imager, day or night, unless it's hot out. As long as you're shooting at things that are warm-blooded, that is.
Note, too, that unless things have changed since I was active in the field, that $1600 monocular is probably a $300 camera married to $1300 worth of optics -- the cheap (yes, $1600 is cheap) thermal imagers work at 8-12 micron, and materials that make decent optics at those wavelengths are pretty exotic.
And things like tanks sort of fade out and in during the transition from daylight to night or vise versa. Sun goes down, background dirt and foliage cool off quickly, sun heated tank stands out brightly. Eventually, it cools down to the temperature of the background and becomes pretty hard to make out, then when dawn comes the reverse starts. :-)
And while they look in shape like lenses, you can't see through them. Typically silicon or germanium are used as far IR lenses.
But if you _start_ the tank, and it doesn't have really good thermal management, it'll glow. Which is how we did so well at the very beginning of the first Gulf war. Until the Iraqis started making fake cardboard tanks and put smudge-pots inside, to heat them up.
Well, they are lenses, and they are transparent -- they're just not transparent at the wavelengths that we can see.
I used to work for FLIR systems; one of the guys there used to work at a semiconductor company and had an 8-inch silicon wafer. It was fun to use for science experiments with our 3-5 imagers, to compare it's transparency in IR to it's opacity in visible.
I looked up some FLIR info a while back and saw the major expense was the lenses. I'm guessing the sensor array wouldn't work well with just a pinhole for a lens? I saw Digi-Key had some sensors but they were low resolution, 8X8 IIRC. It still would be fun to play with, perhaps interpolating between pixels for sub pixel resolution, at least to get an image bigger than 8X8 on a screen. It probably wouldn't be very good but at least maybe you could locate some thermal variation.
We didn't have any silicon wafers handy, but had plenty of prototype far IR imagers to play with. Nice the patterns body contact makes as the body heat is conducted through typical clothing. :-)
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There were various FLIR systems -- some were prototype, some actual production items being sent into the field. FLIR stood for "Far Looking Infra Red", and applied to both the far IR which we have been discussing, and also near IR (just below the frequency (above the wavelength of visible light.) Those near IR systems had big Catadioptric (sp?) (mirror) lenses, and a multi-stage image Intensifier. You could also use standrd visible light lenses with the near IR systems. The night vision scope on the rifles, and later ones with single-stage microchannel intensifiers, used plain visible light optics.
How long do you have to integrate each pixel? A pinhole means very little thermal difference, so you have to average the signal for a long time to see a difference. (Lots of thermal noise from the sensors with that little illumination.)
You could use pure mirror lenses, with just a spider supporting the front mirror, not any transparent support, so the lens should work as well for far IR as for visible light.
And the trick with sensors like that is to scan them to get more coverage. One trick was a rotating multi-faceted mirror, with each facet at a slightly different angle relative to the axis, so it scans a line parallel to the previous one. Of course, this requires a fairly quickly-responding sensor, so likely would need cryogenic cooling to keep the thermal noise down.
I know for IR reflectors I have seen, they are a gold color. Would those mirrors work for far IR?
I have a BOE BOT educational basic stamp robot that has a servo and a "Ping" ultrasonic sensor. The servo sweeps the sensor back and forth, pinging distances to objects at various angles and turns the robot in an open direction. There is a program for the programming computer to read this data and it gives you a graphical representation of what is being detected. I thought about trying that same approach with a single IR temperature sensor but plot a direction and a color representing temperature. If this were fast enough a person could use mirrors like a laser printer uses (old ones anyway) and get a 2D array with each sweep, like a TV scan but with a temperature sensor. Of course this would be limited by the reaction speed of the sensor. Anyway, with moresensors it could be done better. I guess you would have to have curvature in the mirror and focus similar to a lens?
I have thought of the above more as a security system to detect people or animals without emitting IR light that someone can see with night vision. I watch some videos of thermal vision hunting and it really highlights the animals over the background. We have a FLIR camera at work that we inspect electrical cabinets with, shows weak connections that need tightened or replaced before failure, very interesting technology.
Sure. For far IR, it doesn't take much to reflect it. A plain sheet of aluminum looks like a mirror to an IR imager. If you want to use glass as the basis, you need first-surface coatings for the reflection. (That is -- unlike normal home mirrors, the light does not pass through the glass to the metal coating, and then pass through it again. Most glass is pretty opaque to Far IR -- with the exception of specialty things like IRTRAN.
Yes -- but you are missing something that the ping gives you -- distance. Since you are seeing the IR radiated by the object, not something reflected off it from a short pulse from the sensor end, you really don't have distance information.
Yes -- a mirror lens, with a second smaller mirror held in the center of the field of view to reflect it through a hole in the center of the mirror. There are such lenses sold for good SLR cameras, and as really high quality telescopes which can be used for limited astronomical work -- if you live in a place without a lot of light pollution. One of the really nice ones was the Questar.
It will tell you the direction -- but not the distance. If there is only one hot spot, a second system could show you a different angle and where they cross is your target.
I suspect that a polar bear would not be that visible -- they have really good insulation. :-)
Including things like aluminum wiring, which tends to degrade its connection with thermal cycling. (A primary example of the needing tightening).
One intersting thing with something like that -- take a pad of paper, place your hand on it for a few seconds and lift it off. You will see a handprint which will slowly fade away.
And -- if you have someone with a bushy mustache, have him breathe through it, and it will light up as his exhaled breath warms it, and darken as he inhales, cooling it. (Or the opposite, if the system is switched to hot-dark mode. :-)
I think I snipped it, but the part where you mentioned using a second sensor to detect a temperature difference, isn't that how the PIR sensors work?
I used to repair to repair copy machines for about 10 years and most of them had first surface mirrors to reflect the document image to the photoconductive drum. When I did controls engineering one of our customers made automotive lamp assemblies and used aluminum vapor deposition to make the reflective inner housings.
Very interesting technology but the good stuff is pricey, the other day I saw an ad for a thermal imaging rifle scope for $8,XXX .
I was given an HP6110 Officejet all-in-one that couldn't Home at startup. HP's repair instructions for that problem are to buy a newer model. The lamp causes nearby plastic to outgas and fog the front-surface mirror. I cleaned it well enough for home use with CRC Mass Air Flow Sensor Cleaner and a degreased Q-Tip. Is there a better choice?
I used to use rubbing alcohol and a light touch with cotton pads, the surface seems to scratch easy. The alcohol streaks but if you keep rubbing until it dries it seems to work well. The strongest solvent we used in cleaning copy machines was MEK but never needed it on the mirrors IIRC.
"RogerN" fired this volley in news: email@example.com:
Although they're a LOT more expensive than isopropyl alcohol and a cotton ball, 3M puts out a line of singly-pouched little 'nappies' with just the right solvent blend and abrasion-free fiber pad to clean 1st-surface mirrors.
Duh... yeah.... pure aluminum with a 1/10 micron coating of silicon dioxide IS, indeed, easy to scratch!
Of course you have had "experience in the matter". Tell us again about your two (was it) combat tours in Vietnam back when you were, what? Fifteen years old?
As for "how many", who knows? It probably depends on the guy's honesty. Yours, of course register zero, and we all know that you are some feeble "limp dick" that is fantasizing how he really is a big swinger.
I was suggesting two sensors viewing from different locations so you have two lines of sight from sensors to target, and where the lines cross is the location of the target. The temperature sensors give you no distance information.
Yep! With first surface, you don't get unwanted (and dimmer) secondary reflections from the surface of the glass before the light reaches the intended reflecting surface. You don't want "ghosts" in your copies. :-)
That makes nice ones -- and if a transmissive clear coating applied over that (glass, or some similar substance evaporated in the vacuum chamber.
But a vacuum chamber of sufficient size is quite pricey, and you have to tear it down and etch away various deposits every few uses.
The ones which I saw were made for the Army -- some regular production, some prototypes. And making them shock-resistant enough to live on top of an operating rifle adds to the costs. :-)