IR "floodlight" using LEDs?

Buy one or more of the many varieties of IR illuminators readily available (manufactured specifically for the purpose you propose.)

For large areas, if power is available, LEDs may not be the most efficient. Brood lamps with IR filters may be cheaper and they put out a lot of IR.

But if you want ot experiment with some LED arrays, get a bunch of high power 850 to 880 nm (the 940 nm ones do not match the sensitivity of most cameras as well) LEDS and build some arrays. To keep them from getting hot, space the LEDS apart about a diameter or so. You can series quite a few and run them off something like 48 volts DC with a single resistor to limit the current.

I like the LEDs from Vishay like this one:

Since their forward current at rated 100 ma is about 1.5 volts, you can connect something like 25 of them in series with a 120 ohm 2 watt resistor and apply 48 volts DC. This will use almost .1 amp or 4.8 watts of power. But you will probably find that you need a half dozen or more of these arrays to light the area you describe.

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For the long distances, you will need some kind of reflector. And since LEDs, even IR, put out a beam that's already somewhat concentrated, they aren't amenable to being in a reflector. So the best way is to use a regular incandescent lamp., which puts out tons of IR. All you have to do is filter out the visible light and let the IR thru. You can get much more IR that way, since the lamps are natural IR emitters.

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Don Bruder wrote in news:xdGDc.19239$Fo4.251396 @typhoon.sonic.net:

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You also may need to use manual focus on your camera. Depending upon how the auto-focus works on your camera, auto-focus may not work. IR illuminated objects focus at a differnt point than visible light illuminated objects do.

If you are at a fixed distance from a given object and switch from visible light to IR illumination, you will find that you may need to re- adjust the focus on the camera.

cheers

buck

What size shells does your camera take???

Gordon.

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It can chamber Hi-8, 8mm or VHS-C. I find it likes Maxell Hi-8 120s, with the full plastic jacket, best. Less jamming when they're ejected. A couple of years ago, I tried some Sony VHS-C 160s that I found on clearance at Wal-Mart but those kept jamming, and left a lot (to the tune of several feet) of tape residue wrapped around the record head when I cycled the action. Something about those magnum loads just doesn't agree with this camera, I guess, since I had the same problem with the TDK 8mm 160s I tried a few months ago.

And as for your insinuation that this is going to be a poaching tool, five words sum it up nicely: "You *GOTTA* be kidding, right???"

If I should decide I want venison on the table, I can poke my head out the back door (or open the bedroom window, or step out on the deck, or open the living room window, or... You get the picture? Deer are

It's a bit harder, though, to do night-filming, since once the sun goes down, they *DO* get spooky about headlights, hand-held floodlights, flashlights, and other visible light sources.

Here is another very useful trick. Use a light dimmer on a standard incandescent lamp, and turn it down to the point where the lamp is just braaely lit. Now the output is almost entirely IR and a pair of cheap filters can get you a very clean beam of it. So use one of those directional spotlights such as a track light or reading light and put a fairly high wattage bulb inside. Dim to barely glowing. Cover with a piece of red plexiglass and a piece of blue plexiglass. The results will be a very nice sharp spotlight of infrared light that is almost completely invisible even if you stare right into the reflector.

Cheers!

Sir Charles W. Shults III, K. B. B. Xenotech Research

If you put two lamps in series, so that they run at half voltage, you don't need the dimmer.

If you use 250 watt brood lamps (reflector floods with red filters painted on them) you only need to add the blue filter to get rid of the visible.

I have a pair of brood lamps wired in series to hang over our bed for when my wife's arthritis acts up in winter. They are dim enough they we can sleep with them on. But I keep dreaming about developing pictures.

If you has some of these running through sunset, I doubt that animals would pay much attention to them with no further filtering. The Farm Bureau and lots of hardware stores sell these for a few dollars each. And at half voltage, they last a very long time.

It CAN'T be that easy... Can it?!?!?!?

I'll definitely try it. Thanks!

Please let us know how you get on.

I want to do the very same thing - deer, raccoons, possums, foxes, turkeys, ground hogs. We get them all - right up to the back door (handing a raccoon a slice of bread and having it take it with its "hands" is just one of the pleasures).

On a vaguely related note, I have put a UV bulb in one of the outside lights - attracts lots of interesting insects at night and you can get fire-flies to signal en masse if you turn the UV light on and off at about

John.

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Hi, Don, Points taken, no offence meant , I just could not let a joke slip by.

In the UK we don't exactly have deer "outside our door".

I do like your in depth reply.

Kind regards, Gordon.

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I have found that further adding green plexiglass to the red and blue makes the output much less visible still. Haven't tried that with a lamp dimmed to barely glowing however. But with a lamp dimmed that severely, the infrared seen by most cameras will certainly suffer in comparison to longer infrared wavelengths.

With red, green and blue plexiglass, the "visible" output is mostly from nominally infrared wavelengths longer than about 730, maybe 740 nm or so. With a high wattage incandescent at full blast, I suspect it will be dim enough for animals to not notice. CAUTION - do not stare into the beam, since your pupils may be more dilated than without the filters and you might cook your retinas.

- Don Klipstein ( snipped-for-privacy@misty.com)

What kind of bulb is that? An uncoated Fluorescent lamp? I know that the mercury UV lamps with a screw base like the ones they used in dryers have to be on for a few minutes before they put out UV. They wouldn't work if you turned them on and off at 1 Hz. Then there's the neon tube UV lamp with the little beads of mercury inside the tube. It puts out a nasty spectrum of UV with the short wavelengths that can badly 'sunburn' you in ten minutes. I think I still have one of those old timers in the garage.

I think it will be a fluorescent with a special coating (not the same as a blacklight coating - they typically let more - bluish - vis through than that).

Why do they need a few minutes to put out UV? If it's a temperature (elctrode/plasma) issue then warming up before pulsing at 1Hz might keep the temp high enough (especially in a reasonably enclosed fitting).

Chris

Actually, it's an incandescent one from the local grocery store - cost about $5. GE Blacklite 60Watts. Barcode 43168 22767. It's a standard bulb coated in a UV transmitting/vis blocking material.

John.

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In article , Watson A.Name \"Watt Sun - the Dark Remover\" wrote in part:

The drier lamps put out shortwave UV (2537 nm and 184.9 nm) and not much longwave, and won't be that useful for attracting insects. These are now collectors' items. They put out a fair amount of UV before they warm up - not that much different from fluorescent lamps in warmup requirements.

I used to have one - puts out 253.7 nm and not much UV of any other wavelength. I once (25 years ago) saw one in a thrift shop, and it was supposedly a sunlamp. The 253.7 nm wavelength is used for germicidal lamps.

Then there are the high pressure mercury vapor sunlamps - the RS ("reflector sunlamp" floodlight with a medium screw base or the RSM version with the mogul screw base), and some models, mainly by Sperti with bare arc tubes and heating elements as resistive ballasts. These put out plenty of 365 nm (not much effect on human skin) and 313 nm (UVB), and a lesser amount of wavelengths that were shorter but in the UVB range. The mercury vapor pressure in the arc tube when fully warmed up was close to atmospheric pressure, but according to "The High Pressure Mercury Vapor Discharge" by W. Elenbaas these fit the description of high pressure mercury vapor lamps.

- Don Klipstein ( snipped-for-privacy@misty.com)

snipped-for-privacy@manx.misty.com (Don Klipstein) wrote in news: snipped-for-privacy@manx.misty.com:

I actually have one of those "dryer" lamps as you refer to them, except mine is in a hand-held mineral light. It has a filter in front of it to block out most of the visible light. By todays standards it isn't a very bright black light. I have some B.L. leds that are much brighter than the mineral light is. The mineral light has a small ballast on a line cord going to the hand-held part, that encases the bulb. It still works just fine. When you take the filter off, you quickly notice that the bulb is also an ozone producer, as well. But I don't stare at it that way... bad news, for sure. It looks just like the un-coated flourecsent tubes. (I know, I said I didn't look at it.) ;)

cheers

buck

A bit like the sign on the laser cutter "do not look into laser with your remaining good eye"

What about photo flood lights?. They have a bluish coating over the bulb, usually 125W minimum and a lifespan of 3 or 4 hrs?

Joe