IR Illuminator without visible glow

D

Dometrius

n3wb
Dec 24, 2017
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Hi all, just wondering if anyone has found any inexpensive IR illuminators that don't emit a visible glow. Just a bit of background, our baby cam broke several months ago so I got a replacement camera (to be used with the same monitor). But the new camera makes an IR halo around the image. So I purchased an IR illuminator to better illuminate the room recently but the trouble is the red glow - my girls just stare at it instead of going to sleep.

So I am hoping for some advice on a better illuminator without any visible glow (like what the baby camera uses) or maybe a way to mask the glow while still illuminating the room. Thanks!
 
Try a 940nm LED illuminator instead of the 850nm LEDs. The 940nm is farther outside the range of visible light to human eye. It is also more outside the range of most sensors, so you will probably have a slight degradation of available light for the cam in IR mode.
 
I have 940nm and it's good, IF you have a good cam (Dahua Starlight).
Not even a slight glimse of visible red, but as handipalm said it's not as powerful as 850nm.
I had a good Dlink cam before and it did'nt se any 940-IR at all.
Be aware that they don't reach very long so select 90 degrees for wider angle at close distances.

I bought some 9w "Felt" brand driven at 220v AC.

There is another thread where they tested 850nm with pictures.


Brgds TheSwede
 
Also, sometimes it's a good idea to have visible IR just to show that there is surveilance cams pointing at You. Or might be .....


Brgds S
 
I have bought bandpassfilters on EBay from England that filters out just the IR part (850) so no red glow and powerful emission.
Have’nt tested them yet.
 
TheSwede said:
I have bought bandpassfilters on EBay from England that filters out just the IR part (850) so no red glow and powerful emission.
Have’nt tested them yet.
Click to expand...

Wait, so you bought filters to block the 850 nm wavelength ... to put in front of your 850nm IR illuminators?
 
If the 850nm filter is put in front of an 850nm, the filter will be lit up. And as bp2008 mentioned, it will block the illumination.
If the 850nm filter is put in front of a cam that uses 850nm Ir LEDs, the filter will be lit up brightly. It will be worse than when using a camera to look through a house window. At night, the clear glass reflects too much Ir. And window glass allows 850nm to pass through, unlike a filter....

IR differences question
It wavelength
IR Cut Filters - please help a quasi newbie
 
Couldnt the IR light be located behind an object that would block direct visible view from the sleeping babies / children and at an angle that would allow the IR light to reflect off of the ceiling to illuminate the subject area. Camera orientation could be set to minimize or eliminate the brightness of the reflected ceiling in the FOV.
 
The filter won't allow 850nm to pass. Imagine if the filter was a piece of paper. Sure, some light would be bounced to the ceiling. But the Ir would still light up the paper.
Secondly, the Ir illumination wouldn't reach the area that the cam is trained upon....
 
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Dometrius said:
Hi all, just wondering if anyone has found any inexpensive IR illuminators that don't emit a visible glow. Just a bit of background, our baby cam broke several months ago so I got a replacement camera (to be used with the same monitor). But the new camera makes an IR halo around the image. So I purchased an IR illuminator to better illuminate the room recently but the trouble is the red glow - my girls just stare at it instead of going to sleep.

So I am hoping for some advice on a better illuminator without any visible glow (like what the baby camera uses) or maybe a way to mask the glow while still illuminating the room. Thanks!
Click to expand...

I cannot attest to how this works, just thought I'd pass the info below along.

Excerpt from ePlastics:

"... Note: All plexiglass sheet is infrared transmitting. This grade is opaque to visible light and allows infrared light through. Unlike glass, you can put all grades of plexiglass in front of DVR's, cable boxes, DVD players, etc. and your remote control, wireless router, etc. will still work. This particular acrylic material is black and only transmits infrared, which makes it ideal for hiding a CCD video camera."

The cheapest and smallest size I see is below but you could cut it up and use it A LOT ! Maybe they'll send you a sample?

Plexiglass Sheets Infrared Transmitting 0.080" X 24" X 48" 3143 Infrared Transmitting Acrylic Sheet ==>> here
 
Filters that look black to your eyes but allow IR to pass will not eliminate the red glow. Many cameras use this type of filter in front of their IR LEDs already to create a more seamless aesthetic, but of course you still see the glow at night because your eyes are mildly sensitive to 850nm infrared and the filter isn't blocking it.

CVZA8mg.jpg



The earlier suggestion to point the 850nm illuminator at the ceiling is a good one. It will still reflect a good amount of IR into the room, but it will be much more spread out, making it harder to see, and probably would be less of a distraction for the baby.
 
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In a past life, I helped design and build cameras for vehicles, including cams that had to be stealthy. So we used 940nm. So that the LEDs weren't visible in daylight, the cam front cover was molded in black plastic that allowed 940nm light to pass, but not visible light. The front cover had a small piece of very transparent glass embedded in it, right in front of the cam lens.
To the human eye, the LEDs couldn't be seen during the day, or at night when they were powered on. We regularly used our phone cameras if we needed to check that all the LEDs were on....
TonyR said:
This particular acrylic material is black and only transmits infrared, which makes it ideal for hiding a CCD video camera.
Click to expand...
That's an interesting claim. So the CCTV camera can pick up objects in the infrared spectrum. What happens during the day? You'd still light up the scene with IR, and record in b&w? I imagine the daytime images would be better than nightime images, since daylight includes Ir....
 
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Fastb said:
That's an interesting claim. So the CCTV camera can pick up objects in the infrared spectrum. What happens during the day? You'd still light up the scene with IR, and record in b&w? I imagine the daytime images would be better than nightime images, since daylight includes Ir....
Click to expand...

Yeah, daylight includes a huge amount of infrared, which is why cameras need to have mechanical IR filters to block it out, otherwise it totally destroys color vision! A camera behind one of those filters would be able to see very well during the day, even though it would be all but invisible to a passer-by.
 
bp2008 said:
A camera behind one of those filters would be able to see very well during the day, even though it would be all but invisible to a passer-by.
Click to expand...
Behind the 850nm filter, that's true.
Behind the IR trans-missive acrylic material mentioned above, not so true. Which is why I quibbled with the following:
TonyR said:
This particular acrylic material is black and only transmits infrared, which makes it ideal for hiding a CCD video camera."
Click to expand...

I'm not sure what purpose an Ir-only camera serves..... It won't see color in daytime...

Just to clarify for forum readers....
 
TonyR said:
I cannot attest to how this works, just thought I'd pass the info below along.
Click to expand...

And to quote Sgt. Schultz of the old TV series "Hogan's Heroes" ('65-71)..."I know NOTHING!" :blankstare:
 
I remember Hogan's Hero's and other series from the 70's. That ages me. An important point, which I'll make below....

A couple of years ago, I asked my team to work on Saturday. They ranged from 20YO to 50+ YO. I ordered Teriyaki lunch.
When the food arrived, I walked to the spead-out crew, announcing: "The Vittles are Here"
When I reached a couple of millennials.
One looked up and asked "What's a vittle?"
I said "No such thing as a "Vittle" (singular). "The word is plural only, ie: "Vittles"
A more puzzled look on his face.
I said "Just follow me"
As my 9 person multi-generational team was enjoying their Teriyaki lunch, I asked:
"Who knows what vittles are?"
Everyone except the two millennials raised their hands. Which caused millennial embarrassment.
IMHO: Millenials often believe they're smarter than older folks. If the older generation knows something that the millennials don't, they'll check Google.

Our engineering facility was RF shielded, due to our radio work. To google "Vittles", they'd have to walk to the parking lot.

Over lunch, the team talked about the Beverly Hillbillies for a while.
Millennials, flustered since they clueless, and couldn't google "Vittles", said in an unbelieving tone:
"A TV series about Hillbillies? Seriously? You shi**ing me? I don't believe you guys!"

The rest of the crew spontaneously broke into song:
"Come and listen to a story 'bout a man named Jed
Poor mountaineer barely kept his family fed
Then one day he was shooting for some food,
And up through the ground come a bubbling crude
(Oil that is, black gold, Texas tea)"​

The millennials, dumbfounded, didn't know what to think. Their coworkers, the Boomers, GenX, GenY, etc all had some common knowledge that Millennials were oblivious about. A blow to ego.
Their typical attitude was they could run circles around older generations.
They tried to recover: "That Beverly Hillbilly TV show doesn't matter these days!"

Over that lunch, I worked to unify the crew. We grew up in different times. Generational Superiority in Attitude is counter productive to team work.

@TonyR
Quoting from Hogan's Hero's or Beverly Hillbillies may have generational-baggage. Careful...

Respectfully,
Fastb
 
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It's not a IR cut filter, they are clear.
850nm bandPASSfilter, it will filter out anything else but pass the 850.
Then it depends on how selective it is, how steep the curves is around 850nm
It looks as a black plastic square, pointed at the sun it's black.

I will test it during the weekend and hopefully post some pics of the IR emitter, with and without filter and the spot on the grass with and without filter to se how much it will attenuate the desired 850.
 
First, a little history and my only experience with IR... sorry if I'm verbose or if off topic.

In the mid 70's and into the 90's, 3M designed and built Xenon-strobe emitters called 'Opticom' that used a visible light, flashing Xenon strobe of narrow frequency and specific rise time and duration. It was mounted generally atop the cab of fire trucks and in some cases, ambulances and police cars.

An optical detector mounted atop the traffic signal heads or mast arms pointed in the direction of travel of emergency vehicles. When those equipped with the Opticom emitter placed it into service the detector would pass that signal on to a receiver in the traffic signal cabinet. The receiver would analyze the signal from the strobe, decode and validate the signal. If valid, a command was issued to preempt the traffic signal and provide a green signal to the emergency vehicle as soon as possible. The flashing strobe was visible, very bright but was rapid enough (8 to 10 pulses per second, I believe) to be displayed legally by emergency vehicles, according to local jurisdiction regulations.

Later it was decided by a transportation agency in Northern California to use the Opticom system on public buses to encourage ridership, lower smog, etc. The Opticom system would insure the green signal would be awarded a little sooner to the bus but not at the expense of serving at least a minimum vehicle green time to vehicles that were preempted, and also after allowing a full pedestrian clearance time (the flashing 'Don't Walk' or orange 'upraised hand') so as to not endanger pedestrians that had received the 'Walk' or white 'walking man' symbol.

The Opticom emitter for a bus modulated at a lower frequency so when decoded by the receiver it would determine that the priority for the preemption of the traffic signal would be low for a bus, and not an emergency vehicle (highest priority).

Because the bus is not considered an emergency vehicle, the state's motor vehicle code required that a dark filter be placed over the emitter so the light would not be visible to people and motorists. I do not recall the wavelength if the IR that made it through the filter (it's been about 35 years for me) but the detectors on the traffic signal mast arms would pick up IR.

Over time, the UV light emitted by the Xenon tube would cause a reaction with the Lexan IR filter making it totally opaque dead-center of the filter after about 2 years and the bus could not preempt the traffic signal. I would remove the filter and polish the inside center with automotive rubbing compound; a huge amount of green stuff would be left on my rag from the IR-passing Lexan. I'd re-install it and all was well with the Opticom preemption on that bus for another couple of years.

That's it! Thanks for indulging me. :cool:

P.S. - @Fastb , I'm an old fart now, too old to carry ANY baggage!
 
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