trying to build an infrared flashlight

Hey guys, I have a bunch of Infrared LEDs, and I want to stick them inside an LED flashlight. Are there any out there that are easily moddable for such an application?

The LEDs I have are 5mm (30 deg) 1.2v (1.6v max) @ 20mA, I have maybe 50 of them. I'd like to avoid changing the LED driver board if possible.

Any suggestions?

You would have to wire 3 of them in series to match the ~3.6v most white/blue LEDs need, or use dropping resistors with them to drop the excess 2.4v.

An inexpensive multi-led flashlight, say a 14 led flashlight, that uses a battery carrier to hold 3 AAA's might be what your after. You would need to modify the battery carrier so the 3 AAA's are in parallel to give you a 1.5 volt source. Unsolder the old leds from the circuit board and install your infra red units. The 14 led model, the 21, and the 28 led model all run the leds direct drive so there's no driver to complicate things.

Mag solitair, or any 1 cell light with a nimh cell ought to do it with a minimal resistor added at most.

Good luck. /ubbthreads/images/graemlins/popcorn.gif

My brother was just asking about this..

Is IR light dangerous, the way UV is??

[ QUOTE ]
ACMarina said:
My brother was just asking about this..

Is IR light dangerous, the way UV is??

[/ QUOTE ]

Nope. The photon energy (what makes UV dangerous) is lower than visable light, not higher (like UV is).

Safe at reasonable levels.

Doug Owen

I replaced the bulb in my minimag with one of the infrared LEDs... the light it makes is pretty good, but I can only fit the one LED in the reflector. I was hoping for a 2dmag size body.

without infrared sight:


with infrared:


The mini mag just didn't 'throw' far enough I guess.

Is this one any good?
http://www.in2thelight.com/model329cpf.htm

That flashlight is not suitable because of it's electronic 3 way switch. The switch needs more voltage than your infra red leds. Go with the 28 led regular on/off switch model that looks identical. The bezel unscrews from the tapered head and allows very easy removal of the round circuit board that the original leds are soldered to. The plastic battery carrier would be very easy to modify so the three AAA's are in parallel. No fuss, no muss.

To modify the battery carrier you would only have to bridge a 1/16 of an inch gap between 2 bits of metal on the inner top and 2 bits of metal on the inner bottom of the carrier.

Almost (if not completely) off topic - when you look through a welding helmet or mask or whatever, is the eyepiece an Infrared filter? I got to watch a guy weld the other day and was amazed at how you went from seeing absolutely nothing to seeing everything clear as day with this helmet. And it looked like an IR filter to me..

I just ordered the 28 on/off model... i'll let you guys know how the modification goes.
The cool thing about the LEDs I have is that they don't have that weak reddish light that is visible in the regular spectrum...

One of my infrared cameras has some built in LEDs, and in pitch black you can see a faint red glow coming from them. That sucks.

When removing the original leds, you may find that using wider, rather than narrower, desoldering braid speeds up the process. Bypass the 1.5 mm braid and opt for 3mm instead. It's the right width for that particular board. In a pinch, you can find it at your local Radio Shack store but it will be cheaper at a proper electronic component warehouse store. Sounds like you have some decent IR leds to work with. Quite a few of them bleed light into the visible spectrum. Please keep us posted on the progress of your mod. Enquiring minds want to know.

ACMarina: Most of the welding glass filters you would come across are poor IR filters but have very good UV blocking properties. There are some that block IR to various degrees but the common #10, #12, and #14 welder's glass are not the most effective for limiting IR light. If you ever get the chance, check out the "automatic" filter welding hoods. They have a glass port that dims automatically when subjected to intense light. The reaction time of these electronic glass filters is amazingly fast.

trident-

Any updates to share?