"Arfa Daily" wrote in message
...

"Lostgallifreyan" wrote in message
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"Arfa Daily" wrote in
:

I really
think that I'm going to have to buy one, and attack it with the
Dremmel

Set to with zeal, my son. If I had a dremel, I would. Probably.

Did find this though:
http://www.claremicronix.com/datashe...0Sheet%20Rev05
3107.pdf
Again, clickable: http://tinyurl.com/2kf3jv

That's interesting because it shows 90% efficiency as I hoped might be
had, from a circuit with no large smoothing capacitor. It's just one tiny
IC driving a MOSFET and using an inductor. I don't know how big that
inductor is, but not very, I imagine. Maybe similar to the one on the
module on the eBay page I linked to earlier. A series chain of three or
four LED's might well be driven directly from the mains, and all fitted
inside one of those small lamp capsules. Heat dispersal might be tight,
but
doable, especially in those lamps with the fine louvre shells to allow
convection to get in amongst the doings.

Well, that's not strictly true. The issue of where the input voltage comes
from, is carefully avoided in the data sheet. It only shows that the chip
can operate from a DC input range of 8 to 450v. To get the DC input from
the mains, would still require a bridge and smoothing cap. However, looks
like a useful chip, and a good candidate for the back end processing. It
claims that it can drive "hundreds" of LEDs in series / parallel strings.
Still reserving judgement at this time ...

Arfa
Here's a really interesting site

http://www.oksolar.com/led/led_color_chart.htm

Follow the various page links to the chromaticity chart, and " More
information on LEDs" at the bottom. I didn't realise that they were already
in use in street lighting. There is mention of higher colour temperatures
improving human night vision. There is also an interesting LED colour chart,
which shows one at 4500K called "incandescent". A couple of years back, I
was in Disney when they put on a show in front of the Magic Castle. There
was a stage spot set up on the top of a pole, projecting a brilliant white
beam of considerable strength. I didn't take much notice of it, until it
suddenly changed colour. During the show, it produced a whole range of
colours, but I couldn't see that the enclosure was anything like big enough
to accommodate a coloured gel wheel. I remember wondering at the time, if
this had been implemented using very high power RGB LEDs. I suppose that it
is also possible that it could have been a plasma lamp with dichroic mirrors
and LCD panels. Are any LEDs actually powerful enough to make stage lighting
from ? Can they be mounted in any way that allows light collection and
direction through beam forming optics ?

Arfa