| Use your webcam in the dark. – Part 2 |
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| Finding a better light source |
Last update: 2005-04-14 |
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From this in normal light (without IR filter)
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to this in total darkness
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to this with two different IR LED types
Note – You can click on all pictures to see a full size version |
So, in part 1 I tried to use 10 regular IR LED’s (CQY99) as illumination for my modified Philips PCVC740k webcam. It did work well, but using 10 LED’s takes up a lot of space, at the same time as they’re not that efficient. So can we do this better? I looked trough all IR LED’s at my preferred supplier (Elfa in Stockholm), and came up with one LED that was interesting. (By the way, Elfa ships all over the world, but I’m sure that you can find a similar supplier in your country)
So, I found a LED called HSDL-4220 with a brother called HSDL-4230. The difference between these are the angle of the emitted beam. The 4220 emits a 30° beam while 4230 emits a 17° beam. And the 4220 emits 38mW/sr while 4230 emits 75mW/sr, where the difference is due to the angle of the beam. Electrically they’re the same. The datasheet for them is here.
The continuous electrical specifications for them are 875nm centre, max 100mA, 1.5V. At a 100mA the 4220 delivers 76mW/sr and 4230 delivers 150mW/sr (in the middle that is). The LED emits a small amount of red light when running on 50 and 100mA.
Now, let’s have a look at the test rig and the pictures of the emitted light from the IR LED’s.
I’ve used a similar setup as in the first part as this will enable me to experiment with the values more flexibly.
As you can see the 4230 really lights up, and I got very exited about it when I first took this picture.
Next, let’s have a result with all the test projections will the different IR LED’s.
So, what’s the conclusion?
Of first the 4230 (17° beam) I actually were a bit disappointed. The beam is so focused that in my 1.5m test setup I got circles on the wall.
| 1*4230 100mA
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3*4230 100mA all focused in the middle
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| 2*4230 50mA each
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3*4230 100mA focused on three points
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As you can see there is nothing wrong with the intensity in it self, but the way it looks (!) makes it unusable for my needs.
As for the 4220 the results were a..lot..better..
| 1*4220 100mA
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3*4220 100mA
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10*CQY99 20mA
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Even only one 4220 LED outperforms the 10* CQY99 that I used earlier. And I guess that I could get ever smoother results on the three 4220 if a managed to focus them a little more spread, but I’ll do that some other time…
By the way, I noticed a smooth headache coming on while doing these experiments! You might want to avoid looking into the LED’s as I really doesn’t know if it good or bad for you. After all 3*4230 at 100mA generates 450mW of light that your eye can’t protect itself from.
If you know anything about it then drop me a email, before I loose my eyesight 
Note. Looking into an IR light source might (?!) damage your eyesight. I don’t take any responsibility for any personal damages, but hey, I can still see good 
(or at least I’m under that impression.)
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June 21st, 2005 at 4:04
“hey, I can still see good
(or at least I’m under that impression.)”
*as he crashes into the doorjam on the way out of his office*
June 24th, 2005 at 13:33
hmmm. i think IR does do somthing to your eyes, i have forgotten what though. I think its to do with radiation.
June 28th, 2005 at 10:28
Chris:
It looks like if you were making your experiments in total darkness, so probably
the problem with your headache comes from your eye trying to catch light where there
is not. Your iris makes efforts, wide open, to let pass light that doesn’t arrive,
so the wear is reflected in headache. As you remark in your text, it is not a good
idea looking straight into a lit LED like the one you’re using (no one would make
it in a pointer LASER, I think), for the emitted power is so great that it could
be dangerous for retina integrity.
My best wills to your investigations, which I hope you’ll get on…
July 27th, 2005 at 4:06
I got this from searching within PubMed
Cataracts occur frequently among workers who deal with hot material such as molten glass or steel, as a result of exposure to intense infra-red radiation (i.r.) emitted from it.
It is suggested that i.r. cataracts in the workplace result from the generation of heat by absorption of i.r. in the cornea and heat conduction to the lens.
This absorbtion depends on the emitted power from the IR led over the surface area of your retina.
October 10th, 2005 at 5:40
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October 25th, 2005 at 10:27
I don’t think this kind of IR could be dangerous for your eyes. UV makes you blind not IR, that’s why we wear sunglasses.
Most of camera are using IR for their auto-focus system, and I never heard about people getting blind because of this.
October 25th, 2005 at 11:20
Hmm, I guess you have a point! Thanks!
November 18th, 2005 at 15:24
Hi – my work involves infra-red lasers, and I can tell you the following:
1) Near Infra-red causes burns to the retina at high powers.
2) The problem is that the blink reflex doesnt work with IR, so you dont realise you’re getting burnt
3) IR lasers are generally considered to be eye safe for powers below 1mW
4) IR Lasers above 5mW are considered definitely an eye hazard
So I would recommend being careful, and not looking at the LED at close range –
at larger distance the beam spread means that not all the energy enters your eye,
but at short distances you could do yourself permanent damage.
(A laser is just a LED with much tighter beam spread, and so all the laser light can enter the eye
at large distances. )
Treat it the same way as you would a high-power white LED – you wouldn’t stare into that would you!
December 8th, 2005 at 6:56
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April 17th, 2006 at 9:34
It looks like if you were making your experiments in total darkness, so probably
the problem with your headache comes from your eye trying to catch light where there
is not. Your iris makes efforts, wide open, to let pass light that doesn’t arrive,
April 17th, 2006 at 9:38
I can still see good (or at least I’m under that impression.)â€Â
May 8th, 2006 at 21:23
Hi – my work involves infra-red lasers, and I can tell you the following:
1) Near Infra-red causes burns to the retina at high powers.
May 8th, 2006 at 21:24
Most of camera are using IR for their auto-focus system, and I never heard about people getting blind because of this.
May 9th, 2006 at 16:59
Hi,
I would definitely say that it isn’t intelligent to look into lit LED’s.
Otherwise, thanks for the great project, just what I have been looking for.!
May 20th, 2006 at 1:26
I never heard about people getting blind because of this.
May 20th, 2006 at 4:59
It looks like if you were making your experiments in total darkness, so probably
the problem with your headache comes from your eye trying to catch light where there
is not. Your iris makes efforts, wide open, to let pass light that doesn’t arrive,
June 3rd, 2006 at 7:30
Hi,
I would definitely say that it isn’t intelligent to look into lit LED’s.
Otherwise, thanks for the great project, just what I have been looking for.!
September 12th, 2006 at 2:30
I would definitely say that it isn’t intelligent to look into lit LED’s.
September 12th, 2006 at 2:33
Most of camera are using IR for their auto-focus system, and I never heard about people getting blind because of this.
October 20th, 2006 at 4:35
It looks like if you were making your experiments in total darkness, so probably
the problem with your headache comes from your eye trying to catch light where there
is not.
November 6th, 2006 at 18:08
I don’t think this kind of IR could be dangerous for your eyes. UV makes you blind not IR, that’s why we wear sunglasses.
August 25th, 2007 at 10:07
Cataracts occur frequently among workers who deal with hot material such as molten glass or steel, as a result of exposure to intense infra-red radiation (i.r.) emitted from it.
August 25th, 2007 at 10:09
so the wear is reflected in headache. As you remark in your text, it is not a good
idea looking straight into a lit LED like the one you’re using (no one would make
March 19th, 2008 at 9:26
Warning man, IR rays just COOK your eyes!
Te proof is that you CAN’T use a negative film to protect your eyes while looking at a solar eclipse, as you’ll THINK it’s shielding, as it shields VISIBLE light, but the sun IR will BURN your eye!
And negative film is what you use to get an IR cam from a standard cam, right?
April 7th, 2008 at 18:05
Hi ther my mane is Jimmy. i have installed a few night vision camera in a vets holding room, and the ? has come up about the camara uses Infrared LED for it’s night vision. Are there any long trem problems with being under the LED for a long time frams.. i have not been able to find any info about this can u help???
July 13th, 2008 at 14:07
“(A laser is just a LED with much tighter beam spread, and so all the laser light can enter the eye
at large distances. )”
Not to nitpick, but a laser is very different than an LED. A laser emits coherent, virtually monochromatic light, while an LED emits over a broad frequency range. Some lasers are based on LEDs (i.e. diode lasers), but are also based on many other materials (dye lasers, rubies etc.).
I would guess that lasers at the right wavelength would be more dangerous than leds not only because all the energy is focused in a narrow spatial range, but also in a narrow wavelength range.