Building Infra Red Light Sources With Regular Lights

[Oneironaut] sent us another IR hack. This time it is a writeup on the best ways to create IR light sources from regular lights. Since normal flashlight bulbs emit a broad enough spectrum to include visible light and IR light, this basically comes down to filtering. [Oneironaut] explores different light sources and different materials in depth, along with great pictures to show his results. This is a great resource if you’re needing to do some night vision for cheap.

23 thoughts on “Building Infra Red Light Sources With Regular Lights

  1. Edmund Scientific (used to) sell a glass IR pass filter that is cheap and happens to exactly fit a Mag-light AA flashlight. It’s visual wavelength “leakage” is close to zero, and used with a Gen II intensifier enables clear images of objects which are hundreds of feet away when beam is focused to a spot. IR LED arrays are more energy efficient, but a retired incandescent flash light gives you IR at a much smaller cost, in money or construction time.

  2. That bottle in the photo is an older Baileys bottle, and it has decent IR pass abilities as well. I did not add that the the first video though, as it was already long enough!

    I am always looking for new IR passing materials, especially those that can withstand high heat.

    The 35mm film was ok, but it melts or degrades from the light after time.


  3. A couple of years ago I did something similar.
    I used theater gels or stage gels.
    They are used along with spot lights to create different color light.
    I believe there were two specific colors; cobalt blue and a red gel. These are made of mylar and can withstand high heat. I made mine using a portable 100,000 candle power flashlight. Worked great.


  4. Aliexpress have various camera specific and plain IR pass filters for betwen $10 and $20 each – nothing like the understandably prohibitively expensive filters quoted from a camera store!

  5. A tungsten-filament bulb will do a great job of emitting infrared even when it is severely underpowered. I would recommend experimenting with powering bulbs off of lower voltage sources than they are designed for, and seeing if you still get sufficient infrared radiation for your application.
    Side effect: the bulb will effectively never burn out, and you will use less power from your battery.

  6. @tyco
    I second that. Tungsten filament bulbs emit near-visible IR. With a proper filter able to absorb the visible spectrum and able to support high temperatures (tungsten filament bulbs are mostly used for heating purposes), I think it is possible to cloak the IR source, in the visible light spectrum of course.

  7. Great info here, thanks.
    I will try the underpowered bulb idea and report back. I would imagine a clear bulb would be better than a soft white.

    I also found a 2500 watt infrared heating bulb in my junk box, and will have to give it a try. unfortunately, it gives off a lot of visible red as well.

    On a side note, I was really surprised at how well my black light (UV) worked with the small camera I used to make the videos. It seems that the CCD is more sensitive to UV than even infrared.


  8. I experimented w/ this quite a bit some time back for a paranormal group. I finally ended up w/ a 12v halogen flood light, a PWM, and some gel filters. It produced the best results I’ve seen anywhere. Only downside, you had to use a 12v .. but w/ the PWM, a 7ah sla would last all night.

  9. @Bob Spafford, ehrichweiss:

    Edmund Optics split off their Edmund Scientific division in 2001. So many of the cool optics they used to sell aren’t available anymore through the Edmund Scientific catalog.

    Now they primarily concentrate on industrial customers (and charge much higher prices).

  10. Oops! The old man is way behind the times! Yes, after posting, I went to Edmund Scientific and it’s all kids stuff now. A Google search for IR pass filters was disappointing. It looks like the days of the $3 IR pass to fit a Mag-Light are history. If you don’t need a focused long beam, IR LEDs are looking better at the prices I’m finding for filters. C’est la vie!

  11. The Baileys bottle just “happened” to be in my lab at the time, so I got to the bottom of it quickly and then tested it with the Halogen light.

    I found the floppy disk to have IR pass abilities sometime in the early 80s when I was messing around with night vision and a crude digitizer I built for my C64.

    Yah, I’m old.

    The plastic packing in a box of chocolates (like Pot of Gold” also had some IR pass abilities.


  12. Ok, gunna get flamed again, but…

    If you go to this site, you have to join or login or whatever to post comments or ask questions.

    I’m good with that, I understand there are wankers hiding behind modems and distance, but…

    Some “nutjob” has a “project” about their “ion ray” which you have to be a member, login, whatever to see anything about what they are on about.

    How paranoid can you be?

    Incidentally, before you go to all the trouble, expense, ect, of putting an IR filter in front of your spotlight, do what I did and build a PWM controller!
    Way before your rechargeable spotlight gets close to visible light, your camera can see it!
    Not only that, but you get hours out of a charge!
    I discovered this one night trying to video bandicoots.
    Way after your battery has been able to produce even a visible glow, your video camera on “night shot” can “see” it.

    No filter is needed!

    Just build a PWM circuit with a 555 and an FET!
    I put a “bypass” switch on my Arlec spotlight that puts my cheap ass PWM controller inline with the lamp.
    Best thing is, instead of 30 mins, you get a couple of hours out of a charge!
    The lamp filament doesn’t even glow visibly without looking through my Sony mini-DV!
    And doesn’t “blow out” the exposure.

    Sorry for the rant, but this is a better way of doing IR illumination.

  13. @Cyberteque

    You are correct, my forum requires a login in order to post, and I plan to keep it that way.

    Since I do all of the projects on LucideScience in my spare time and then offer support to those trying to build them, I have little time to spend deleting spammers and moderate negative people.

    Youtube is a perfect example of what I am talking about (99% negativity and spam comments), and I have ZERO patience for it.

    Some people have a positive view of creativity, while others think everyone that tries something that differs from their own “gospel” is just a “nutjob”.

    Just Sayin’

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