Subject:
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IR leds, was Re: Spybot studies: SetTxDirection() confusion
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Newsgroups:
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lugnet.robotics.spybotics
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Date:
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Fri, 14 Nov 2003 12:53:52 GMT
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Viewed:
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6510 times
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... Just reading an old post and saw my mistake: of course 880 nm is closer to
red (650nm) than 940nm !!!
Here is the correct text I should have sent :
"I think these emitters are different wavelength, 880nm for the pointing up one,
940nm for the others. 880nm radiation is very close to red wavelength range and
is easily seen by cameras CCD, even though they generally include an IR filter
to get a good color balance with high IR lighting. 940nm on the contrary is
filtered out before reaching CCD."
To illustrate my point, here is a photo of similar performances IR Leds, one
880nm and one 940nm, shot with a Coolpix 900 that had a rather weak IR filter :
http://www.brickshelf.com/gallery/Philo/Misc/irleds.jpg
Philo
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Message is in Reply To:
 | | Re: Spybot studies: SetTxDirection() confusion
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| (...) I think these emitters are different wavelength, 940nm for the pointing up one, 880nm for the others. 940nm radiation is very close to red wavelength range and is easily seen by cameras CCD, even though they generally include an IR filter to (...) (21 years ago, 7-Nov-03, to lugnet.robotics.spybotics)
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