Need help with an IR LED...

DreamCrusher

Newly Enlightened
Joined
Feb 6, 2009
Messages
12
Location
Occupied Mexico
I'm hoping one of you fine folks can help me, as your knowledge of LEDs and electronics in general amazes me.

What I'm looking for, if it's even possible, is a small IR LED flasher that is visible to both NVG's and FLIR.

Something like this:

http://www.lapolicegear.com/noname32.html

but that can be picked up by both regular NVGs as well as FLIR cameras.

Is there an LED that's capable of doing both, or will it have to be two separate LEDs?

What say you??
 

Benson

Flashlight Enthusiast
Joined
Feb 15, 2009
Messages
1,145
From Wikipedia, FLIR systems operate in the 3-5 or 8-12 micron ranges. (For reference, blackbody emission at 20C peaks around 10 micron wavelength, while ~700 K (~400C) gives 4 microns.)

I'm not sure you can even get LEDs at those wavelengths (and if you can, the heat probably contributes more than the light!), but maybe a "coldwire" (underdriven incandescent) would work -- crank it up till it just glows a very dark red. I think the normal way to make infrared emitters for this sort of thing is filtered blackbody radiation, but not sure. (You can skip filtration if a threshold-of-visible red glow is bright enough for your sensors, and dim enough (to the eye) for invisibility -- if you do need more brightness, either add more area, or crank the voltage, current, and brightness up and add a filter to block visible light.)
 
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