Assuming over-riding the opto couplers to falsely confirm to the system
micro that the arc is struck and the lamp is lit (maybe requiring a
delay) firstly, with the lamp ps disconnected.
Then I intend in the first instance to buy 5x 1.2W white LEDs, 3500K, 20
degree, for proof of concept. Assuming that sort of works then get
perhaps 10 more, going down to 2700K or 3000K or perhaps (unlikely)
4000K and lenses to colimate to 2 degrees. Set inside a reversed conical
silvered glass of an ex-lamp to direct spillover light into the
colourwheel/light tunnel aperture.
The intended LEDs are 11x10mm footprint so can be mounted quite close to
the colourwheel(for 5 anyway) on a spherical back mount. I may as well
retain the original fans, perhapps knocked back a bit for less noise
intrusion later on.

When coming to scaling up I originally was thinking of using a sectored
curvi-linear silvered reflector from PIR units (with faned air cooling)
but have since come across 2 degree lens converters for these LEDs so
may as well go with them and shine directly from a larger spherical
backing mount, directly to the colourwheel aperture.

I'd be interested in any suggestions or comments other than of the I
would not bother type of replies. Anyone happen to know what the light
wastage proportion is of a non-ideal paraboloid reflector and non-point
source discharge lamp is? I'm aware proper LED projectors have active
drives to RGB LEDs and not colour wheels but there are a lot of
ink-jet-printer-syndrome surplus HD video projectors around with too
expensive short-arc lamp costs to replace

Some bods been here before with converting a couple of types of
discharge lamp converters
http://www.blue-room.org.uk/index.php?showtopic=54833
http://www.blue-room.org.uk/index.ph...#entry4265 04

If anyone is interested, my exploration of inside a standard domestic
GU10 LED lamp (to see if they were all in series or mixed series/parallel)
240V,2W.
Breaking in:- hold the bulb in a glove and heat the dome cover with
"low" temp hot air and prize off with a needle. With old soldering iron
destroy the epoxy join between the , not obvious as silvered, pcb to the
lamp housing. The slight greeen colouration is due to the reflection of
the green dye of the pcb which is not glass fibre reinforced it seems,
maybe epoxy substrate only. Prize the pcb away.
No glass breakage at any stage.
Overlay of this one marked JH-GU10-20
HV ac side 1M//0.33uF 400V dropper and 1/4W resistor size
fuse/inductor/fuseable resistor? pink colour with red black brown, or
reverse order, colour bands, about 0.4R to small SMD MB6S bridge
rectifier.
LV quasi-DC side SMD 510R dropper to 20 LEDs in series.
White ceramic cap is cemented to the glass of the lamp.
Bench ps 50V across LED string and 510R all LEDs just lit
54V and 0.5V over 510R and about 2.6V over each LED some sort of low
level brightness.
With 75% mains (240V that is) 6.5V DVM dc over 510R
or 5.5V DVM ac over 510R
100% mains 9.1V "DC" or 7.2V as "AC" reading over the 510R

Have you calculated whether you can cram enough LEDs into that space to get
the same brightness level as the discharge lamp? Or are you expecting to learn
from the test?

I'd like to point out that is no such thing as -- nor can there be -- a white
LED. LEDs are necessarily limited to a narrow band of wavelengths. * All (???)
white LEDs are (I assume) a blue LED with a yellow-fluorescing phosphor. **

This /looks/ white to the eye, but the red and green wavelengths needed for
color reproduction aren't present.

Unless your white LEDs contain red, green, and blue LEDs, I don't think this
is going to work.

* This is actually a good thing if one is trying to match a specific color
space, and you can manufacture LEDs whose wavelengths correspond to the three
primaries.

** I'm thinking of indicator lights and such. Lamps to replace incandescent
lighting would necessarily have to put out red and green, or colors wouldn't
look right.

On 27/09/2013 14:46, William Sommerwerck wrote:
Have you calculated whether you can cram enough LEDs into that space to
get the same brightness level as the discharge lamp? Or are you
expecting to learn from the test?

I'd like to point out that is no such thing as -- nor can there be -- a
white LED. LEDs are necessarily limited to a narrow band of wavelengths.
* All (???) white LEDs are (I assume) a blue LED with a
yellow-fluorescing phosphor. **

This /looks/ white to the eye, but the red and green wavelengths needed
for color reproduction aren't present.

Unless your white LEDs contain red, green, and blue LEDs, I don't think
this is going to work.

* This is actually a good thing if one is trying to match a specific
color space, and you can manufacture LEDs whose wavelengths correspond
to the three primaries.

** I'm thinking of indicator lights and such. Lamps to replace
incandescent lighting would necessarily have to put out red and green,
or colors wouldn't look right.

Its not possible to do any calculation as to brightness because it is
impossible to find the true loss of light from a conventional
distributed ie not point source discharge lamp source and non ideal
reflector, I would guess that 2/3 of the rated light does not get into
the apaature and then how to calculat the proportion that is at such an
angle to the light tunnel to the active chip and multiple reflections
that little of that gets to where it is wanted, axially along the 2
inches or so of narrow diameter light pipe .

As for colour rendition it is unlikely to be any worse than the current
situation of having to place a rose-pink filter over the projector lens
to get some red into the image as the lamp must be too far into the blue
end of the spectrum tio be compensated for in the setable timing of the
colourwheel.

So in both cases very much a suck it and see, seat-of-ones pants
situation, but worth a go, if you've seen the price of these supposed
replacement discharge lamps

On 27/09/2013 14:46, William Sommerwerck wrote:
Have you calculated whether you can cram enough LEDs into that space to
get the same brightness level as the discharge lamp? Or are you
expecting to learn from the test?

I'd like to point out that is no such thing as -- nor can there be -- a
white LED. LEDs are necessarily limited to a narrow band of wavelengths.
* All (???) white LEDs are (I assume) a blue LED with a
yellow-fluorescing phosphor. **

This /looks/ white to the eye, but the red and green wavelengths needed
for color reproduction aren't present.

Unless your white LEDs contain red, green, and blue LEDs, I don't think
this is going to work.

* This is actually a good thing if one is trying to match a specific
color space, and you can manufacture LEDs whose wavelengths correspond
to the three primaries.

** I'm thinking of indicator lights and such. Lamps to replace
incandescent lighting would necessarily have to put out red and green,
or colors wouldn't look right.

I've had another look at the product data and the 2 degree lenses are 4
degree , in normal terminology

I don't know what chromaticity means but for the 3500 deg K version a Cx
of about .4 and Cy of about .39
A bit more graphic the spectrum is continuous and smooth "bell curve"
peak shifted 40nm from 550nm of the standard eye response curve to 590nm
and the 50% points broader apart at 150nm compared to 100nm of the eye
and a 50% down peak at 460nm which I suppose is the potential bugbear
for such a lamp conversion

"N_Cook" wrote in message ...

I don't know what chromaticity means but for the 3500 deg K version a Cx
of about .4 and Cy of about .39
A bit more graphic the spectrum is continuous and smooth "bell curve"
peak shifted 40nm from 550nm of the standard eye response curve to 590nm
and the 50% points broader apart at 150nm compared to 100nm of the eye
and a 50% down peak at 460nm which I suppose is the potential bugbear
for such a lamp conversion

Could you send me the data sheet, or its URL? I'd like to take a look.

On 27/09/2013 16:12, William Sommerwerck wrote:
"N_Cook" wrote in message ...
I don't know what chromaticity means but for the 3500 deg K version a Cx
of about .4 and Cy of about .39
A bit more graphic the spectrum is continuous and smooth "bell curve"
peak shifted 40nm from 550nm of the standard eye response curve to 590nm
and the 50% points broader apart at 150nm compared to 100nm of the eye
and a 50% down peak at 460nm which I suppose is the potential bugbear
for such a lamp conversion

Could you send me the data sheet, or its URL? I'd like to take a look.



LEDs, I did not find a uk/us URL
http://www.promelec.ru/pdf/LCWW51M.pdf
lenses
http://www.farnell.com/datasheets/607410.pdf

On Fri, 27 Sep 2013 14:34:59 +0100, N_Cook wrote:

Then I intend in the first instance to buy 5x 1.2W white LEDs, 3500K, 20
degree, for proof of concept. (...)

I've done this with marginal sucess. The problem is focus. The
original light has all the light coming from roughly a single point.
An array of 5 LED's will distribute the light over a much larger area.
It will work well with light from the central LED using the original
reflector, but the outer LED's will be wasted and splattered all over
the room.

You don't really need the original reflector if the light source has
its own forward facing reflector. Try cramming an MR16 bulb in place
of the projector bulb and reflector. The smaller size MR16 lamps
might fit.

Mo
http://www.instructables.com/answers/Change-a-projector-lamp-to-LED-/

--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

Could you send me the data sheet, or its URL?
I'd like to take a look.

http://www.promelec.ru/pdf/LCWW51M.pdf

I'm not an expert on this subject (though I do know a little). My gut reaction
is this...

The color reproduction index is only 80. That's poor. That doesn't mean that
the LED won't work -- but it will probably need appropriate filtering that
won't be easy to achieve.

The spectral emission (p11) isn't particularly flat -- and definitely not
smooth -- no doubt one of the reasons for the poor CRI.

I don't think you're going to get pleasing results.

On 27/09/2013 18:35, Jeff Liebermann wrote:
On Fri, 27 Sep 2013 14:34:59 +0100, N_Cook wrote:

Then I intend in the first instance to buy 5x 1.2W white LEDs, 3500K, 20
degree, for proof of concept. (...)

I've done this with marginal sucess. The problem is focus. The
original light has all the light coming from roughly a single point.
An array of 5 LED's will distribute the light over a much larger area.
It will work well with light from the central LED using the original
reflector, but the outer LED's will be wasted and splattered all over
the room.

You don't really need the original reflector if the light source has
its own forward facing reflector. Try cramming an MR16 bulb in place
of the projector bulb and reflector. The smaller size MR16 lamps
might fit.

Mo
http://www.instructables.com/answers/Change-a-projector-lamp-to-LED-/


All the discharge lamps in video projectors , I/ve seen have an
electrode and squashed , not optically conductive glass, axial exactly
in line to where you want the light to go.
With directional 20 degree central LEDs, and lensed 4 degree ones
off-axis. will direct most of the energy directly to the half inch
aperature , without any reflectors . Reflectors just to mop up spill over .
I can see some high power red LEDs being added to counter the blue sub=peak

On Fri, 27 Sep 2013 19:56:58 +0100, N_Cook wrote:

All the discharge lamps in video projectors , I/ve seen have an
electrode and squashed , not optically conductive glass, axial exactly
in line to where you want the light to go.

True. However, the lamp I was replacing originally looked like these:
http://www.porters.com/general-accessories/projector-bulbs/projector-studio-bulb-dyh.html
http://www.porters.com/general-accessories/projector-bulbs/eys-projection-lamp.html

Note that some LED projectors use RGB LED's with three PWM modulators
to control the output level of each color LED in order to get a better
looking "white". In particular, the micro DLP projectors use RGB
LED's. Some use white LED's but methinks they look awful on the
screen.

--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

"William Sommer******"

I'd like to point out that is no such thing as -- nor can there be -- a
white LED. LEDs are necessarily limited to a narrow band of wavelengths. *
All (???) white LEDs are (I assume) a blue LED with a yellow-fluorescing
phosphor. **

This /looks/ white to the eye, but the red and green wavelengths needed
for color reproduction aren't present.


** As ****ing usual, the Somer****** fool just makes stuff up.

Anyone can Google "white led" and get the facts.

There is plenty of green orange and red in the light from regular white
leds.


..... Phil

"N_Cook" wrote in message
...
Assuming over-riding the opto couplers to falsely confirm to the system
micro that the arc is struck and the lamp is lit (maybe requiring a delay)
firstly, with the lamp ps disconnected.
Then I intend in the first instance to buy 5x 1.2W white LEDs, 3500K, 20
degree, for proof of concept. Assuming that sort of works then get perhaps
10 more, going down to 2700K or 3000K or perhaps (unlikely) 4000K and
lenses to colimate to 2 degrees. Set inside a reversed conical silvered
glass of an ex-lamp to direct spillover light into the colourwheel/light
tunnel aperture.
The intended LEDs are 11x10mm footprint so can be mounted quite close to
the colourwheel(for 5 anyway) on a spherical back mount. I may as well
retain the original fans, perhapps knocked back a bit for less noise
intrusion later on.

When coming to scaling up I originally was thinking of using a sectored
curvi-linear silvered reflector from PIR units (with faned air cooling)
but have since come across 2 degree lens converters for these LEDs so may
as well go with them and shine directly from a larger spherical backing
mount, directly to the colourwheel aperture.

I'd be interested in any suggestions or comments other than of the I would
not bother type of replies.

Sorry to be one of those people, but based on some experiments that I've
recently been doing with high power LEDs, I think you are going to be
****ing in the wind. A few watts worth is not going to come close. I have
been playing with some 10 watt types with appropriate collimating reflectors
and lenses. Whilst they are 'blinding' to look at directly, you could easily
do it with a pair of sunglasses on. You most certainly could not do that
with a 200 watt discharge lamp. Also, they require substantial amounts of
directly fan-cooled heatsinking, which makes the assembly physically quite
large. A further problem with high power LEDs, is that they are made from
multiple chips on a single die. This actually makes it rather difficult to
get an even density light from them. Because they are substantially
flat-plane light radiators, the light tends to remain in 'dots' through the
collimating and focusing optics.

I do a lot of work on pro and semi pro lighting fixtures - such as moving
heads of the type that you see in use on TV shows like Strictly and
X-Factor. The ones at the small to medium end typically use discharge lamps
in the range 150 to 575 watts. There are now some at the lower end of the
market which use LEDs, and I can tell you that no matter how powerful a LED
that they employ, they cannot hold a candle (Ha!) to the 'real deal' with a
discharge lamp in them.

So, whilst you may get some results that are just about acceptable in the
right circumstances, I honestly feel, based on practical experience, that
you will get anywhere near matching the performance of the discharge lamp
originally fitted.

Arfa

"N_Cook" wrote in message
...
On 27/09/2013 14:46, William Sommerwerck wrote:
Have you calculated whether you can cram enough LEDs into that space to
get the same brightness level as the discharge lamp? Or are you
expecting to learn from the test?

I'd like to point out that is no such thing as -- nor can there be -- a
white LED. LEDs are necessarily limited to a narrow band of wavelengths.
* All (???) white LEDs are (I assume) a blue LED with a
yellow-fluorescing phosphor. **

This /looks/ white to the eye, but the red and green wavelengths needed
for color reproduction aren't present.

Unless your white LEDs contain red, green, and blue LEDs, I don't think
this is going to work.

* This is actually a good thing if one is trying to match a specific
color space, and you can manufacture LEDs whose wavelengths correspond
to the three primaries.

** I'm thinking of indicator lights and such. Lamps to replace
incandescent lighting would necessarily have to put out red and green,
or colors wouldn't look right.

I've had another look at the product data and the 2 degree lenses are 4
degree , in normal terminology

I don't know what chromaticity means but for the 3500 deg K version a Cx
of about .4 and Cy of about .39
A bit more graphic the spectrum is continuous and smooth "bell curve" peak
shifted 40nm from 550nm of the standard eye response curve to 590nm
and the 50% points broader apart at 150nm compared to 100nm of the eye and
a 50% down peak at 460nm which I suppose is the potential bugbear for such
a lamp conversion


That triangular diagram that you see with red, green and blue respectively
at each corner and white in the middle, and intended to show every possible
colour that can be derived from additive mixing of those three colours, is
called a chromaticity diagram. It famously used to be used to show that a
colour CRT cannot (truly) produce brown.

Arfa

"N_Cook" wrote in message
...
On 27/09/2013 18:35, Jeff Liebermann wrote:
On Fri, 27 Sep 2013 14:34:59 +0100, N_Cook wrote:

Then I intend in the first instance to buy 5x 1.2W white LEDs, 3500K, 20
degree, for proof of concept. (...)

I've done this with marginal sucess. The problem is focus. The
original light has all the light coming from roughly a single point.
An array of 5 LED's will distribute the light over a much larger area.
It will work well with light from the central LED using the original
reflector, but the outer LED's will be wasted and splattered all over
the room.

You don't really need the original reflector if the light source has
its own forward facing reflector. Try cramming an MR16 bulb in place
of the projector bulb and reflector. The smaller size MR16 lamps
might fit.

Mo
http://www.instructables.com/answers/Change-a-projector-lamp-to-LED-/


All the discharge lamps in video projectors , I/ve seen have an electrode
and squashed , not optically conductive glass, axial exactly in line to
where you want the light to go.
With directional 20 degree central LEDs, and lensed 4 degree ones
off-axis. will direct most of the energy directly to the half inch
aperature , without any reflectors . Reflectors just to mop up spill over
.
I can see some high power red LEDs being added to counter the blue
sub=peak


My experiments have shown that the use of a collimating reflector
specifically designed for the LED package being used, brightens the forward
beam significantly ...

Arfa

"Arfa Daily" wrote in message ...

That triangular diagram with red, green and blue at the corners
and white in the middle, and intended to show every possible colour that can
be derived from additive mixing of those three
colours, is called a chromaticity diagram. It famously used to be
used to show that a colour CRT cannot (truly) produce brown.

You've never seen a '70s RCA set? Brown was about the only color it /could/
produce (along with some blues and yellows, if I recall correctly).

Brown is actually a very dark red.

On 28/09/2013 02:28, Arfa Daily wrote:


"N_Cook" wrote in message
...
Assuming over-riding the opto couplers to falsely confirm to the
system micro that the arc is struck and the lamp is lit (maybe
requiring a delay) firstly, with the lamp ps disconnected.
Then I intend in the first instance to buy 5x 1.2W white LEDs, 3500K,
20 degree, for proof of concept. Assuming that sort of works then get
perhaps 10 more, going down to 2700K or 3000K or perhaps (unlikely)
4000K and lenses to colimate to 2 degrees. Set inside a reversed
conical silvered glass of an ex-lamp to direct spillover light into
the colourwheel/light tunnel aperture.
The intended LEDs are 11x10mm footprint so can be mounted quite close
to the colourwheel(for 5 anyway) on a spherical back mount. I may as
well retain the original fans, perhapps knocked back a bit for less
noise intrusion later on.

When coming to scaling up I originally was thinking of using a
sectored curvi-linear silvered reflector from PIR units (with faned
air cooling) but have since come across 2 degree lens converters for
these LEDs so may as well go with them and shine directly from a
larger spherical backing mount, directly to the colourwheel aperture.

I'd be interested in any suggestions or comments other than of the I
would not bother type of replies.

Sorry to be one of those people, but based on some experiments that I've
recently been doing with high power LEDs, I think you are going to be
****ing in the wind. A few watts worth is not going to come close. I
have been playing with some 10 watt types with appropriate collimating
reflectors and lenses. Whilst they are 'blinding' to look at directly,
you could easily do it with a pair of sunglasses on. You most certainly
could not do that with a 200 watt discharge lamp. Also, they require
substantial amounts of directly fan-cooled heatsinking, which makes the
assembly physically quite large. A further problem with high power LEDs,
is that they are made from multiple chips on a single die. This actually
makes it rather difficult to get an even density light from them.
Because they are substantially flat-plane light radiators, the light
tends to remain in 'dots' through the collimating and focusing optics.

I do a lot of work on pro and semi pro lighting fixtures - such as
moving heads of the type that you see in use on TV shows like Strictly
and X-Factor. The ones at the small to medium end typically use
discharge lamps in the range 150 to 575 watts. There are now some at the
lower end of the market which use LEDs, and I can tell you that no
matter how powerful a LED that they employ, they cannot hold a candle
(Ha!) to the 'real deal' with a discharge lamp in them.

So, whilst you may get some results that are just about acceptable in
the right circumstances, I honestly feel, based on practical experience,
that you will get anywhere near matching the performance of the
discharge lamp originally fitted.

Arfa

Have you tried the video projector use rather than Gobo type things
where you are not trying to squeeze light along a small aperature light
tunnel? I've not found the data out there but I suspect the vast
majority of the light available to a gobo setup just does not get into a
light tunnel setup , so if you can direct all your LED lamps into that
tunnel then the overall requirement is much lower than normal ratings
would suggest.
The use of this video projector is for text and graphics so colour
rendition of the likes of flesh tones is not too critical, very rarely
showing any video as such.

On 27/09/2013 18:43, William Sommerwerck wrote:
Could you send me the data sheet, or its URL?
I'd like to take a look.

http://www.promelec.ru/pdf/LCWW51M.pdf

I'm not an expert on this subject (though I do know a little). My gut
reaction
is this...

The color reproduction index is only 80. That's poor. That doesn't mean
that
the LED won't work -- but it will probably need appropriate filtering that
won't be easy to achieve.

The spectral emission (p11) isn't particularly flat -- and definitely not
smooth -- no doubt one of the reasons for the poor CRI.

I don't think you're going to get pleasing results.

Intended use in the main part is for projecting text and graphics so as
long as there is a colour difference, any colour difference almost,
rather than correct colour rendering that is all that is required , a
rare pic with a green flesh tone or something does not really matter too
much

I've moved away from thinking about using lenses as they restrict the
footprint size. If I double stack the LEDs then a spacing of centres
about 8.5mm is possible and so 14 LEDs in a 32mm diameter. So can be
quite close to the light tunnel and 20 degree beam spread is fine and
outer LEDs approach angle will still only be 30 degrees or so, and a
reasonable proportion of that will reflect only a few times and
substantially get to the DLP chip. Will still try 5 LEDs initially.
Will power up individually at only 100mA or so and set the angles of
each individual LED for maximum brightness at a simulated window with a
photodiode , then wire all in series and make a more substantial back
mount before transfering to the projector

On 27/09/2013 11:34 PM, N_Cook wrote:
Assuming over-riding the opto couplers to falsely confirm to the system
micro that the arc is struck and the lamp is lit (maybe requiring a
delay) firstly, with the lamp ps disconnected.
Then I intend in the first instance to buy 5x 1.2W white LEDs, 3500K, 20
degree, for proof of concept. Assuming that sort of works then get
perhaps 10 more, going down to 2700K or 3000K or perhaps (unlikely)
4000K and lenses to colimate to 2 degrees. Set inside a reversed conical
silvered glass of an ex-lamp to direct spillover light into the
colourwheel/light tunnel aperture.
The intended LEDs are 11x10mm footprint so can be mounted quite close to
the colourwheel(for 5 anyway) on a spherical back mount. I may as well
retain the original fans, perhapps knocked back a bit for less noise
intrusion later on.

When coming to scaling up I originally was thinking of using a sectored
curvi-linear silvered reflector from PIR units (with faned air cooling)
but have since come across 2 degree lens converters for these LEDs so
may as well go with them and shine directly from a larger spherical
backing mount, directly to the colourwheel aperture.

I'd be interested in any suggestions or comments other than of the I
would not bother type of replies. Anyone happen to know what the light
wastage proportion is of a non-ideal paraboloid reflector and non-point
source discharge lamp is? I'm aware proper LED projectors have active
drives to RGB LEDs and not colour wheels but there are a lot of
ink-jet-printer-syndrome surplus HD video projectors around with too
expensive short-arc lamp costs to replace

Some bods been here before with converting a couple of types of
discharge lamp converters
http://www.blue-room.org.uk/index.php?showtopic=54833
http://www.blue-room.org.uk/index.ph...#entry4265 04


If anyone is interested, my exploration of inside a standard domestic
GU10 LED lamp (to see if they were all in series or mixed series/parallel)
240V,2W.
Breaking in:- hold the bulb in a glove and heat the dome cover with
"low" temp hot air and prize off with a needle. With old soldering iron
destroy the epoxy join between the , not obvious as silvered, pcb to the
lamp housing. The slight greeen colouration is due to the reflection of
the green dye of the pcb which is not glass fibre reinforced it seems,
maybe epoxy substrate only. Prize the pcb away.
No glass breakage at any stage.
Overlay of this one marked JH-GU10-20
HV ac side 1M//0.33uF 400V dropper and 1/4W resistor size
fuse/inductor/fuseable resistor? pink colour with red black brown, or
reverse order, colour bands, about 0.4R to small SMD MB6S bridge
rectifier.
LV quasi-DC side SMD 510R dropper to 20 LEDs in series.
White ceramic cap is cemented to the glass of the lamp.
Bench ps 50V across LED string and 510R all LEDs just lit
54V and 0.5V over 510R and about 2.6V over each LED some sort of low
level brightness.
With 75% mains (240V that is) 6.5V DVM dc over 510R
or 5.5V DVM ac over 510R
100% mains 9.1V "DC" or 7.2V as "AC" reading over the 510R

**What a waste of time and effort. The best LEDs are approximately
similar efficiency to that of halide lamps. As others have stated, the
big problem will be that you are substituting a compact light source
with a rather diffuse one. The optics are not designed for such use.

--
Trevor Wilson www.rageaudio.com.au

On 28/09/2013 22:08, Trevor Wilson wrote:
On 27/09/2013 11:34 PM, N_Cook wrote:



**What a waste of time and effort. The best LEDs are approximately
similar efficiency to that of halide lamps. As others have stated, the
big problem will be that you are substituting a compact light source
with a rather diffuse one. The optics are not designed for such use.


But the lamps used in video projectors are ,in effect, not compact. The
direct light path from the reasonably compact source is blocked by an
electrode and non optical structural glass lump, relying on the mirror
surface of the light tunnel / light pipe to average out/balance-up the
light coming in at all sorts of angles, off the parabaloid reflector

"William Sommerwerck" wrote in message
...
"Arfa Daily" wrote in message ...

That triangular diagram with red, green and blue at the corners
and white in the middle, and intended to show every possible colour that
can be derived from additive mixing of those three
colours, is called a chromaticity diagram. It famously used to be
used to show that a colour CRT cannot (truly) produce brown.

You've never seen a '70s RCA set? Brown was about the only color it
/could/ produce (along with some blues and yellows, if I recall
correctly).

Brown is actually a very dark red.


ISTR from my college days that brown is known as a non-spectral colour, and
cannot truly be produced by mixing R, G and B in any proportion, and this is
shown by the chromaticity diagram. Rather, it is a perceived colour that is
'worked out' by the brain, based on experience and surrounding colours.

Arfa

"Arfa Daily" wrote in message ...
"William Sommerwerck" wrote in message
...
"Arfa Daily" wrote in message ...

Brown is actually a very dark red.

ISTR from my college days that brown is known as a non-spectral colour, and
cannot truly be produced by mixing R, G and B in any proportion, and this is
shown by the chromaticity diagram. Rather, it is a perceived colour that is
'worked out' by the brain, based on experience and surrounding colours.

I'm not sure about that.

When I said "very dark", I meant having a low value. The chromaticity diagram
does not include value -- only hue and chroma. "Brown" is how the eye
interprets reds of low value.

On 29/09/2013 5:50 PM, N_Cook wrote:
On 28/09/2013 22:08, Trevor Wilson wrote:
On 27/09/2013 11:34 PM, N_Cook wrote:



**What a waste of time and effort. The best LEDs are approximately
similar efficiency to that of halide lamps. As others have stated, the
big problem will be that you are substituting a compact light source
with a rather diffuse one. The optics are not designed for such use.


But the lamps used in video projectors are ,in effect, not compact. The
direct light path from the reasonably compact source is blocked by an
electrode and non optical structural glass lump, relying on the mirror
surface of the light tunnel / light pipe to average out/balance-up the
light coming in at all sorts of angles, off the parabaloid reflector

**NO. By the time you try to shove 200 Watts of LEDs into the enclosure
(including apprpriate heat sinking) You're not going to be able to focus
the whole thing properly. It's a daft idea, unless you are prepared to
use MUCH less LED power (say 15 Watts) and a consequent huge drop in
Lumens.

BTW: The light from a parabolic reflector does not come off at all sorts
of angles.

--
Trevor Wilson www.rageaudio.com.au

That Osram with built in lens is discontinued, only came out 3 years ago.
I'm getting 7 of the LCW W5SM, white 2700K 120 degree and matching 7 off
6 degree hex shaped lenses.
The off the shelf 7 cell hex cluster lens is for parallel , not focused.
Using a 5 to 6 inch ball as a jig I'll combine the 7 as a focused cell.
With the lenses at 85% transmission, brings the 75 lumen per LED down to
64 lumen, so x 7 =450 lumen. Some heatsinky type protrusions added to
the LEDs to catch the fanned air.
When new the projector was rated 2000 lumen, although still taking 200W
, the light output is now much less. Combined with the poor optics of
these lamp setups I suspect fully directed into the light pipe 450 lm is
not much different to the present discharge lamp situation. Still plenty
of room to add another 6 plus lenses around the periphery to bring up to
900 lm.
Playing around with a scrapped colour wheel dicroic disc and assorted
white LEDs the red transmission , to eye anyway , is a lot lower than G
and B.
So I will get a number of red 100mA 5mm , 15 degree standard size LEDs
to add red, perhaps 6 at the interstices of the lenses, mounted to the
rear and between the SMD LEDs plus maybe another 6 around the periphery
to infill.
Good progress with the silvered "cone" for mop-up, front of PAR lamp
removed and bulb removed, about 3/4 way through grinding through the
thick glass with cintrided disc, to remove the barrel part. Previous
attempt with thinner glass photoflood failed. If I was brave or had a
load of these sort of lamps, I would try the old bottle cutter routine,
freezer spray and a ring of "fuse" wire around , fired up for the cut

Well that was very successful, a job I've never done before. Not a cone
but the nearest I could find with
a good silvered internal surface and right sort of dimensions. The
thinnest part of the glass 4.5mm thickening to 7mm as 12 flutes around
the stem, but a neat ground-glass cut.
So I have a spillover reflector with 70mm internal diameter available
for the LED assembly, down to 21mm diameter opening for the colour wheel
aperature (from memory about 12mm) and 43mm axially.
It will be a couple of weeks before I can get some time to convert the
projector . But in the meantime anyone any ideas how to measure the
intensity of the LED assembly at the axis and focus of the array, with
any sort of accuracy (no known "standard candles" etc in my
possession)?, for anyone else coming down the same path. My uncalibrated
luxmeter , I doubt goes that high plus probably would melt, as would any
of the plastic neutral density filter I have and placed in the path of
that beam

How about some photos of what you are doing, most of what you are describing is WAY over my knowledge of optics and lenses.

On 30/09/2013 17:10, wrote:
How about some photos of what you are doing, most of what you are describing is WAY over my knowledge of optics and lenses.


Its more bodging than optics. I'll take a few pics along the way.
I've just noticed on the LED lens makers datasheet if you put 7 of their
1.2W white light LEDs in a specialised version of one of their lens
structures , as I will be doing in a different manner, and directing to
a 12mm waist , you end up with 3,000,000 lux there . All I need then is
some deuterium pellets.
I think I'll need more than neutral density 4 stop Lee Filter , I just
tried black silicone rubber sheet and that is more like x0.001 light
attenuation with an odd colour cast from white LED

On Friday, September 27, 2013 9:41:54 PM UTC-4, William Sommerwerck wrote:


You've never seen a '70s RCA set? Brown was about the only color it /could/

produce (along with some blues and yellows, if I recall correctly).

You don't recall correctly...

RCA color TVs were always the most accurate, with a single exception: the CTC38 (I'm pretty sure about the number, that was over 40 years ago) was a low end toilet made for two years for big stores and buying groups and had a tube lineup distinctly different from the better models, and they were made in the 60s not 70s. By 1971, RCA was running the extremely accurate and reliable XL100, or the mostly transistorized hybrid XL (sweep tubes only), which also was an excellent performer.

Mid 60s Zeniths were known for crappy color as they aged, but would respond well to replacing the demodulator transformers and doing a full color alignment.

"John-Del" wrote in message
...

On Friday, September 27, 2013 9:41:54 PM UTC-4, William Sommerwerck wrote:

You've never seen a '70s RCA set? Brown was about the only color it
/could/ produce (along with some blues and yellows, if I recall correctly).

You don't recall correctly...

Oh, but I do. I might have the decade wrong, but there was a time when RCA
sets had horrible color. Why, I don't know. My memory is that they were the
most-common color TV in the motels where I stayed when travelling for Bendix.
They were invariably tres-lousy.

I saw a CTC-100 maybe 45 years ago, and I remember it having an excellent
picture.

Trevor Wilson wrote:
On 29/09/2013 5:50 PM, N_Cook wrote:
On 28/09/2013 22:08, Trevor Wilson wrote:
On 27/09/2013 11:34 PM, N_Cook wrote:



**What a waste of time and effort. The best LEDs are approximately
similar efficiency to that of halide lamps. As others have stated, the
big problem will be that you are substituting a compact light source
with a rather diffuse one. The optics are not designed for such use.


But the lamps used in video projectors are ,in effect, not compact. The
direct light path from the reasonably compact source is blocked by an
electrode and non optical structural glass lump, relying on the mirror
surface of the light tunnel / light pipe to average out/balance-up the
light coming in at all sorts of angles, off the parabaloid reflector

**NO. By the time you try to shove 200 Watts of LEDs into the enclosure
(including apprpriate heat sinking) You're not going to be able to focus
the whole thing properly. It's a daft idea, unless you are prepared to
use MUCH less LED power (say 15 Watts) and a consequent huge drop in Lumens.

BTW: The light from a parabolic reflector does not come off at all sorts of angles.

One of my projects was making a light source with multiple colored 5 watt
LEDs. I was also considering white LEDs. First test was using fiber optics.
Problems in getting an even field, trying different lens, diffusors. Second
attempt was using reflectors. Since the project required a fairly compact
unit, I probably would need fluid cooling. Project stalled, but its still
in my mind.

Greg

On 01/10/2013 04:49, gregz wrote:
Trevor Wilson wrote:
On 29/09/2013 5:50 PM, N_Cook wrote:
On 28/09/2013 22:08, Trevor Wilson wrote:
On 27/09/2013 11:34 PM, N_Cook wrote:



**What a waste of time and effort. The best LEDs are approximately
similar efficiency to that of halide lamps. As others have stated, the
big problem will be that you are substituting a compact light source
with a rather diffuse one. The optics are not designed for such use.


But the lamps used in video projectors are ,in effect, not compact. The
direct light path from the reasonably compact source is blocked by an
electrode and non optical structural glass lump, relying on the mirror
surface of the light tunnel / light pipe to average out/balance-up the
light coming in at all sorts of angles, off the parabaloid reflector

**NO. By the time you try to shove 200 Watts of LEDs into the enclosure
(including apprpriate heat sinking) You're not going to be able to focus
the whole thing properly. It's a daft idea, unless you are prepared to
use MUCH less LED power (say 15 Watts) and a consequent huge drop in Lumens.

BTW: The light from a parabolic reflector does not come off at all sorts of angles.

One of my projects was making a light source with multiple colored 5 watt
LEDs. I was also considering white LEDs. First test was using fiber optics.
Problems in getting an even field, trying different lens, diffusors. Second
attempt was using reflectors. Since the project required a fairly compact
unit, I probably would need fluid cooling. Project stalled, but its still
in my mind.

Greg


By 5W I supppose you mean co-planar ready-made assembly
http://docs-europe.electrocomponents...6b80d0828a.pdf
has some cell cluster focusing devices.

On Mon, 30 Sep 2013 15:38:22 -0700 (PDT), John-Del
wrote:

On Friday, September 27, 2013 9:41:54 PM UTC-4, William Sommerwerck wrote:


You've never seen a '70s RCA set? Brown was about the only color it /could/

produce (along with some blues and yellows, if I recall correctly).

You don't recall correctly...

RCA color TVs were always the most accurate, with a single exception: the CTC38 (I'm pretty sure about the number, that was over 40 years ago) was a low end toilet made for two years for big stores and buying groups and had a tube lineup distinctly different from the better models, and they were made in the 60s not 70s. By 1971, RCA was running the extremely accurate and reliable XL100, or the mostly transistorized hybrid XL (sweep tubes only), which also was an excellent performer.

Mid 60s Zeniths were known for crappy color as they aged, but would respond well to replacing the demodulator transformers and doing a full color alignment.
The CTC38s were made from 1969 through 1970. The color demodulator
had a wide angle in the flesh tone area so flesh tones looked
"natural" even if the tint shifted slightly. Yellows were reproduced
as orange because of this feature. The solid state set in 1971,
except for the hv rectifier, was the CTC40. It wasn't like the
following XL100 line because the chassis wasn't modular. Some had an
issue with the color killer circuit killing the color on a normal
color signal. Chuck

On 1/10/2013 1:49 PM, gregz wrote:
Trevor Wilson wrote:
On 29/09/2013 5:50 PM, N_Cook wrote:
On 28/09/2013 22:08, Trevor Wilson wrote:
On 27/09/2013 11:34 PM, N_Cook wrote:



**What a waste of time and effort. The best LEDs are approximately
similar efficiency to that of halide lamps. As others have stated, the
big problem will be that you are substituting a compact light source
with a rather diffuse one. The optics are not designed for such use.


But the lamps used in video projectors are ,in effect, not compact. The
direct light path from the reasonably compact source is blocked by an
electrode and non optical structural glass lump, relying on the mirror
surface of the light tunnel / light pipe to average out/balance-up the
light coming in at all sorts of angles, off the parabaloid reflector

**NO. By the time you try to shove 200 Watts of LEDs into the enclosure
(including apprpriate heat sinking) You're not going to be able to focus
the whole thing properly. It's a daft idea, unless you are prepared to
use MUCH less LED power (say 15 Watts) and a consequent huge drop in Lumens.

BTW: The light from a parabolic reflector does not come off at all sorts of angles.

One of my projects was making a light source with multiple colored 5 watt
LEDs. I was also considering white LEDs. First test was using fiber optics.
Problems in getting an even field, trying different lens, diffusors. Second
attempt was using reflectors. Since the project required a fairly compact
unit, I probably would need fluid cooling. Project stalled, but its still
in my mind.

Greg


**The largest LED array I've used is a 100 Watt array (approx 25mm X
25mm). The cooling system is a fan assisted CPU cooler. The whole lot is
almost double the size of a 250 Watt halide projector lamp (Then there's
the 33 Volt 3 Amp supply. It occupies another 100cc) and reflector. It
delivers around half as much light output as the halide lamp. It is
measurably brighter than a 500 Watt halogen flood lamp. Then there's the
33 Volt 3 Amp supply. It occupies another 100cc.

When using RGB LEDs, I've found that it is best to use a translucent
panel to mix colours.

--
Trevor Wilson www.rageaudio.com.au

**The largest LED array I've used is a 100 Watt array (approx 25mm X
25mm). The cooling system is a fan assisted CPU cooler. The whole lot is
almost double the size of a 250 Watt halide projector lamp (Then there's
the 33 Volt 3 Amp supply. It occupies another 100cc) and reflector. It
delivers around half as much light output as the halide lamp. It is
measurably brighter than a 500 Watt halogen flood lamp. Then there's the
33 Volt 3 Amp supply. It occupies another 100cc.

When using RGB LEDs, I've found that it is best to use a translucent panel
to mix colours.

--
Trevor Wilson www.rageaudio.com.au


I've recently been playing with a 30 watt RGB LED. It's a similar size at
around 25 x 25 mm, and each 'channel' comprises 10 individual LED chips in a
vertical line. I'm using a collimating reflector and lens made to go with
it, and the heatsink supplied with it as part of the package. It is a
heavily finned 'cube' about 50 x 50 x 60 mm and the makers state that it
requires force cooling - and it does - so that adds another 15 mm in fan
depth, and as you say, then there is the power supply.

The reflector does a good job of collecting all of the output from the die,
and the lens does a similarly good job of producing a basic beam. However,
because the R, G and B LEDs are arranged in parallel lines, the colour
mixing, as you have discovered, is poor, and the individual colours are
patchy. I found that this could be completely overcome with only a very tiny
reduction in perceived output, by placing a sheet of translucent polythene
under the face of the lens that is the LED side. I'm talking the stuff
that's like builder's polythene here. Opaque enough that you can't see
detail through it, but still very neutrally light transmissive.

In my experience, LEDs are funny old things when it comes to light output.
As a 'for instance'. LED torches (flashlights) are so bright that you can't
look at them. And yet they are poor at producing a light to see by, and do
little to produce any overall lighting in comparison to a standard
incandescent torch bulb. Basically, go into a dark room with a conventional
torch and a LED torch, and you will see better with the conventional torch.
I have a 10 watt white LED that I've also been playing with, and for some
weeks, it has been sitting on the bench just running. On several occasions
when I have dropped screws etc that have rolled under the bench, I have
picked it up with its power supply, and taken it down to the floor. It
lights the area under the bench like daylight, and yet fallen parts are
still more difficult to spot than they are with a conventional torch. It
might be something to do with either the colour of the light, or the very
stark shadows that it creates ...

Arfa

On 2/10/2013 11:28 AM, Arfa Daily wrote:




**The largest LED array I've used is a 100 Watt array (approx 25mm X
25mm). The cooling system is a fan assisted CPU cooler. The whole lot
is almost double the size of a 250 Watt halide projector lamp (Then
there's the 33 Volt 3 Amp supply. It occupies another 100cc) and
reflector. It delivers around half as much light output as the halide
lamp. It is measurably brighter than a 500 Watt halogen flood lamp.
Then there's the 33 Volt 3 Amp supply. It occupies another 100cc.

When using RGB LEDs, I've found that it is best to use a translucent
panel to mix colours.

--
Trevor Wilson www.rageaudio.com.au


I've recently been playing with a 30 watt RGB LED. It's a similar size
at around 25 x 25 mm, and each 'channel' comprises 10 individual LED
chips in a vertical line. I'm using a collimating reflector and lens
made to go with it, and the heatsink supplied with it as part of the
package. It is a heavily finned 'cube' about 50 x 50 x 60 mm and the
makers state that it requires force cooling - and it does - so that adds
another 15 mm in fan depth, and as you say, then there is the power supply.

**Exactly. LEDs are certainly efficient. Far more efficient than any
incandescent lamp. Discharge lamps, particualarly halides, are a
different matter entirely. LEDs are (presently) not more efficient than
halides or sodium vapour lamps. Of course that may change.


The reflector does a good job of collecting all of the output from the
die, and the lens does a similarly good job of producing a basic beam.
However, because the R, G and B LEDs are arranged in parallel lines, the
colour mixing, as you have discovered, is poor, and the individual
colours are patchy. I found that this could be completely overcome with
only a very tiny reduction in perceived output, by placing a sheet of
translucent polythene under the face of the lens that is the LED side.
I'm talking the stuff that's like builder's polythene here. Opaque
enough that you can't see detail through it, but still very neutrally
light transmissive.

In my experience, LEDs are funny old things when it comes to light
output. As a 'for instance'. LED torches (flashlights) are so bright
that you can't look at them. And yet they are poor at producing a light
to see by, and do little to produce any overall lighting in comparison
to a standard incandescent torch bulb. Basically, go into a dark room
with a conventional torch and a LED torch, and you will see better with
the conventional torch. I have a 10 watt white LED that I've also been
playing with, and for some weeks, it has been sitting on the bench just
running. On several occasions when I have dropped screws etc that have
rolled under the bench, I have picked it up with its power supply, and
taken it down to the floor. It lights the area under the bench like
daylight, and yet fallen parts are still more difficult to spot than
they are with a conventional torch. It might be something to do with
either the colour of the light, or the very stark shadows that it
creates ...

Arfa

**I disagree. One of my torches uses a 2 Watt halogen bulb. It produces
excellent light output, though the reflector tends to provide a pretty
poorly defined pattern. It can be focussed within limited ranges. By
contrast, one of my 1 Watt LED torches blows it away, in every area. In
fact last week, I picked up a 1 Watt LED torch for 7 Bucks, which has a
focus attachment. It is astonishingly good. Except at it's narrowest
focus setting. The rectangular LED chip is easily seen on a wall at 100
Metres. At 2 Metres, the 'dot' is 100mm X 100mm. At it's widest focus
setting, the 'dot' is 2 Metres in diameter. It's so handy I'm buying a
bunch more. I will avoid incandescent torches in the future.

--
Trevor Wilson www.rageaudio.com.au

On 2/10/2013 11:28 AM, Arfa Daily wrote:




**The largest LED array I've used is a 100 Watt array (approx 25mm X
25mm). The cooling system is a fan assisted CPU cooler. The whole lot
is almost double the size of a 250 Watt halide projector lamp (Then
there's the 33 Volt 3 Amp supply. It occupies another 100cc) and
reflector. It delivers around half as much light output as the halide
lamp. It is measurably brighter than a 500 Watt halogen flood lamp.
Then there's the 33 Volt 3 Amp supply. It occupies another 100cc.

When using RGB LEDs, I've found that it is best to use a translucent
panel to mix colours.

--
Trevor Wilson www.rageaudio.com.au


I've recently been playing with a 30 watt RGB LED. It's a similar size
at around 25 x 25 mm, and each 'channel' comprises 10 individual LED
chips in a vertical line. I'm using a collimating reflector and lens
made to go with it, and the heatsink supplied with it as part of the
package. It is a heavily finned 'cube' about 50 x 50 x 60 mm and the
makers state that it requires force cooling - and it does - so that adds
another 15 mm in fan depth, and as you say, then there is the power supply.

The reflector does a good job of collecting all of the output from the
die, and the lens does a similarly good job of producing a basic beam.
However, because the R, G and B LEDs are arranged in parallel lines, the
colour mixing, as you have discovered, is poor, and the individual
colours are patchy. I found that this could be completely overcome with
only a very tiny reduction in perceived output, by placing a sheet of
translucent polythene under the face of the lens that is the LED side.
I'm talking the stuff that's like builder's polythene here. Opaque
enough that you can't see detail through it, but still very neutrally
light transmissive.

In my experience, LEDs are funny old things when it comes to light
output. As a 'for instance'. LED torches (flashlights) are so bright
that you can't look at them. And yet they are poor at producing a light
to see by, and do little to produce any overall lighting in comparison
to a standard incandescent torch bulb. Basically, go into a dark room
with a conventional torch and a LED torch, and you will see better with
the conventional torch. I have a 10 watt white LED that I've also been
playing with, and for some weeks, it has been sitting on the bench just
running. On several occasions when I have dropped screws etc that have
rolled under the bench, I have picked it up with its power supply, and
taken it down to the floor. It lights the area under the bench like
daylight, and yet fallen parts are still more difficult to spot than
they are with a conventional torch. It might be something to do with
either the colour of the light, or the very stark shadows that it
creates ...

Arfa

**BTW: This is the torch I spoke of:

http://www.ozstock.com.au/8108/Super...able-Lens.html

You may find one locally. It's a bloody rip-snorter.

--
Trevor Wilson www.rageaudio.com.au

On 02/10/2013 03:43, Trevor Wilson wrote:
On 2/10/2013 11:28 AM, Arfa Daily wrote:




**The largest LED array I've used is a 100 Watt array (approx 25mm X
25mm). The cooling system is a fan assisted CPU cooler. The whole lot
is almost double the size of a 250 Watt halide projector lamp (Then
there's the 33 Volt 3 Amp supply. It occupies another 100cc) and
reflector. It delivers around half as much light output as the halide
lamp. It is measurably brighter than a 500 Watt halogen flood lamp.
Then there's the 33 Volt 3 Amp supply. It occupies another 100cc.

When using RGB LEDs, I've found that it is best to use a translucent
panel to mix colours.

--
Trevor Wilson www.rageaudio.com.au


I've recently been playing with a 30 watt RGB LED. It's a similar size
at around 25 x 25 mm, and each 'channel' comprises 10 individual LED
chips in a vertical line. I'm using a collimating reflector and lens
made to go with it, and the heatsink supplied with it as part of the
package. It is a heavily finned 'cube' about 50 x 50 x 60 mm and the
makers state that it requires force cooling - and it does - so that adds
another 15 mm in fan depth, and as you say, then there is the power
supply.

The reflector does a good job of collecting all of the output from the
die, and the lens does a similarly good job of producing a basic beam.
However, because the R, G and B LEDs are arranged in parallel lines, the
colour mixing, as you have discovered, is poor, and the individual
colours are patchy. I found that this could be completely overcome with
only a very tiny reduction in perceived output, by placing a sheet of
translucent polythene under the face of the lens that is the LED side.
I'm talking the stuff that's like builder's polythene here. Opaque
enough that you can't see detail through it, but still very neutrally
light transmissive.

In my experience, LEDs are funny old things when it comes to light
output. As a 'for instance'. LED torches (flashlights) are so bright
that you can't look at them. And yet they are poor at producing a light
to see by, and do little to produce any overall lighting in comparison
to a standard incandescent torch bulb. Basically, go into a dark room
with a conventional torch and a LED torch, and you will see better with
the conventional torch. I have a 10 watt white LED that I've also been
playing with, and for some weeks, it has been sitting on the bench just
running. On several occasions when I have dropped screws etc that have
rolled under the bench, I have picked it up with its power supply, and
taken it down to the floor. It lights the area under the bench like
daylight, and yet fallen parts are still more difficult to spot than
they are with a conventional torch. It might be something to do with
either the colour of the light, or the very stark shadows that it
creates ...

Arfa

**BTW: This is the torch I spoke of:

http://www.ozstock.com.au/8108/Super...able-Lens.html


You may find one locally. It's a bloody rip-snorter.


One of those that if you close focus , you can start your campfire
without having to rub two boyscouts together?
an example of the focus mechanics shown in here
docs-europe.electrocomponents.com/webdocs/0d08/0900766b80d0828a.pdf

**BTW: This is the torch I spoke of:

http://www.ozstock.com.au/8108/Super...able-Lens.html

You may find one locally. It's a bloody rip-snorter.

--
Trevor Wilson www.rageaudio.com.au

I'm glad it's "Plash resistant" and has a "Tactical switch". They should be
useful features ... ! :-)

Seriously though, it is a somewhat different design to ones that I've seen
previously, so may be a considerable improvement. It does seem to be a
technology that's evolving quite quickly.

Arfa

I now physically have the LEDs and lenses. 2 immediate problems, both
active faces of the lenses are dead flat. In the pdfs it looked as
though the front faces were surrounded in a ring and I assumed (pdfs not
clear pics) the 4 corner holes of the LEDs would mesh with pips on the
rear of the lens.
They are made for mounting to pcbs not the other way round, so no
provisions for that. So I have to find some 12mm or so diameter thinn
rings to align the front faces to my 5 inch cistern ball valve float as
spherical former, and make some sort of jig for aligning the LEds to the
lenses , plus fixing them together

I'm not used to optically pure plastic, I would have sworn that
examining the LED side of 2 of the lenses then it was flat faced, but
not touched the surfaces, and they contain recesses.
I now have some rings for placement.
The datasheet does not explain the normal placement. LED soldered to
pcb, a non-optical plastic holder placed over the LED, quite loosely.
The holder is .4mm undersized so forcing the lens into it, then
compresses the other end around the LED with little pip under each
corner, but no use made of the 4 holes in the corners.
I think I've worked out how to adapt those holders for my purposes.