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Re: [APD] LED lighting

There are LEDs and there are LEDS. Regular LEDs produce a very narrow freqncy of light directly, usually red and there are a few other dims ones. The super bright LEDS that produce significant light and can be in various diff colors, including white, use a form of fluorescence to produce the light. The have slightly less energy effiiciency than tube fluorescents and very narrow frequency output. The color of the light depends on the material doped on the diode.
 
While one could make an array with super birght LEDs for an aquarium light, it would be a wiring pita with all the number of elements involved, use more energy and give off more not less heat.
 
Any of the energy conversion websites for freeware programs can give the equations for the way too many diff ways that energy is measured. Candela is a measure of the luminous intensity in a particular direction. Measure the amount falling on a specific area and you measure luminance like footlamberts. Not to be confused with illuminance like lux, foot-candles, or lumens/sq meter. Perfectly clear? Right?  Well, try this:
 
http://www.crompton.com/wa3dsp/light/lumin.html
 
 
Super bright LEDs are very practical for special applications and might improve enough to have more practical applications but I'm not tempted to get out my soldering yet.
Good Luck,
 
Scott H.
* * * * * * * * * * * The Northeast Council of Aquarium Societies (NEC) celebrates its 50th year of service at its 31st annual convention, April 7-9, 2006 -- including *An Evening with Aquarium Legends*. Read the speaker list, then download the registration form, and get set to join the fun at what promises to be the year's biggest tropical fish convention. http://northeastcouncil.org/html/ And while you're there, attend the AGA's annual meeting Friday afternoon (2-4pm). This year's speaker is Claus Christensen, Tropica's Managing Director.


----- Original Message ----
From: Stuart Halliday <stuart at stuarthalliday_com>
To: aquatic plants digest <aquatic-plants at actwin_com>
Sent: Tuesday, February 07, 2006 6:20:45 AM
Subject: [APD] LED lighting


I've seen a few white LED strips on sale in my local Maplin hardware store 
and these looked *very* bright and I was wondering if these could be used as 
a low heat equivalent replacement for fluorescent tubes?

Ok, they're not going to be cheaper than tubes. But they will last for years 
(100,000 hours (20 years)), don't fade and will be cooler and more efficient 
than tubes. Plus they are of course very controllable.
(By mixing white with red and green you could control colour temperature 
exactly to simulate sunrise-sunset colours for example).

Has anyone here, experimented with using ultra-bright LEDs yet in tanks?


http://www.maplin.co.uk/Module.aspx?TabID=1&ModuleNo=45981&doy=7m2#spec

These LEDs have a 5200K colour temperature, but replacing a few white ones 
with green, red or blue LEDs would easily adjust the overall light colour.

This strip in the link says its light output is 420 candelas, any idea what 
a basic tube is?


Some of the new high power LEDs have a 120d viewing angle and are very very 
bright.
http://www.omc-uk.com/leds/datasheets/Power%20LED.PDF

IIRC polarised light source penetrate deeper into water too...
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