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..
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
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,
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.
Control systems, embedded software and circuit design
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.
On Sat, 28 May 2016 03:35:59 +0000, DoN. Nichols wrote:
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.
Control systems, embedded software and circuit design
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.
Not unless you can get the squirrels to agree to set themselves on fire
when you want to see them, no.
The sensors aren't very sensitive, and the optics need to be low-f
numbers, which is pretty much the opposite of pinholes.
The original sidewinder missile used a one "pixel" detector and did
pretty good for it's day.
Control systems, embedded software and circuit design
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. :-)
[ ... ]
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
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
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.
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
Duh... yeah.... pure aluminum with a 1/10 micron coating of silicon
dioxide IS, indeed, easy to scratch!
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
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. :-)
I found a video where someone used servos to scan an area with a single IR
sensor and displayed the results, that's what I thought about doing but it
would be too slow for most of what I wanted it for.
I have seen a relatively simple single sensor system - made by
Barnes, IIRC, back in the 1970s. It had a two sided mirror which was
scanned both left-to-right and top to bottom (slower for the latter),
and reflected the image from the IR lens onto the detector moving the
detector in a raster scan pattern. The other side of the mirror had a
modulated light source -- a bit early for LEDs, though possibly that.
More likely to be a neon lamp through a pinhole -- onto some 4x6"
Polaroid film. It took a while, but generated a good image, and one of
the people demonstrating it said that it had convinced him to stop
smoking. He took a scan of his hand before a cigarette, and about five
minutes after one, and the loss of blood flow to the hand rather scared
So -- a slow scan is possible, and useful for certain things.
One possibility is scanning a circuit breaker box -- looking for warm
areas where the wire screws need to be tightened or the breaker
replaced. (Or where the current draw needs to be reduced. :-)
Here's an impressive lens.
<https://theintercept.com/2016/05/25/american-sniper-chris-kyle-distorted-his-military-record-documents-show/ > It probably wouldn't be very good but
So what? Just tell stories about how good it is. Like this.
"Kyle wrote in his memoir that he had 160 ?confirmed kills? as a sniper,
a self-reported statistic."
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
Or, as some say, "Walter Mitty".
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