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Subject: TWL: Re: LED anchor lights
From: Mr O English, Medistat Software (UK) Ltd (owen@XXX.XXX)
Date: Tue Dec 31 2002 - 15:06:52 EST
Hi,
Don't worry about a seizure being caused by colored LEDs. I have spent the
last 25 yrs putting strobe lights of varying frequencies (1-40Hz) in front
of KNOWN epileptics in my daily occupation. These would be 10,000 the power
of a pile of LEDs and are white (very much more provocative) yet only about
1:1000 of these patients produce seizures. We use tungsten discharge tubes
fired by a bank of charged capacitors (for those interested, the units are
built by 'Grass' in Massachutas).
Owen E
----- Original Message -----
From: <LRZeitlin@XXX.XXX>
To: <trawler-world-list@XXX.XXX>
Sent: Wednesday, January 01, 2003 7:23 AM
Subject: TWL: LED anchor lights
> Bob,
>
> I agree that the best attribute of LEDs is their long life rather than
high
> light output. However you can increase the "apparent" brightness of LEDs
for
> use as an anchor light by pulsing them at a rapid rate, usually about 12
to
> 16 pps. This is at or just above the flicker fusion rate for most normal
> adults. The bulbs can temporarily exceed maximum rated steady state light
> output limits when pulsed because of the interpulse cooling. The
perceptual
> effect of the pulsing light is that it is much brighter than a steady
state
> light of the same average output. It is also mildly disturbing to view - a
> perfect attention getter. The only downside is that it might drive some
> susceptible onlookers into epileptic shock.
>
> Larry Z
> _______________________________________________
> http://lists.samurai.com/mailman/listinfo/trawler-world-list
>
>
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