Converting a 200W discharge lamp video projector to LED

[William Sommerwerck]

"Arfa Daily" wrote in message news:MQ42u.8296$je2.4836@fx14.am4...
"William Sommerwerck" <grizzledgeezer@comcast.net> wrote in message
news:l25c55$adg$1@dont-email.me...

"Arfa Daily" wrote in message news:Ilq1u.3812$ku4.1058@fx25.am4...

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.

 

[Arfa Daily]

"William Sommerwerck" <grizzledgeezer@comcast.net> wrote in message
news:l25c55$adg$1@dont-email.me...

"Arfa Daily" wrote in message news:Ilq1u.3812$ku4.1058@fx25.am4...

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

 

[Trevor Wilson]

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

 

[N_Cook]

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

 

[N_Cook]

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

 

[hrhofmann@sbcglobal.net]

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

 

[N_Cook]

On 30/09/2013 17:10, hrhofmann@sbcglobal.net 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

 

[John-Del]

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.

 

[gregz]

Trevor Wilson <trevor@SPAMBLOCKrageaudio.com.au> 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

 

[William Sommerwerck]

"John-Del" wrote in message
news:83e8ff7f-c8da-4bfe-9ea9-428fe1314698@googlegroups.com...

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.

 

[N_Cook]

On 01/10/2013 04:49, gregz wrote:

Trevor Wilson <trevor@SPAMBLOCKrageaudio.com.au> 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.com/webdocs/0d08/0900766b80d0828a.pdf
has some cell cluster focusing devices.

 

[chuck]

On Mon, 30 Sep 2013 15:38:22 -0700 (PDT), John-Del <ohger1s@aol.com>
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

 

[Trevor Wilson]

On 1/10/2013 1:49 PM, gregz wrote:

Trevor Wilson <trevor@SPAMBLOCKrageaudio.com.au> 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

 

[Arfa Daily]

**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

 

[Trevor Wilson]

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-FREE-Ozstock-Day--CREE-LED-Powered-Torch-with-Adjustable-Lens.html

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

--
Trevor Wilson www.rageaudio.com.au

 

[Trevor Wilson]

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

 

[N_Cook]

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-FREE-Ozstock-Day--CREE-LED-Powered-Torch-with-Adjustable-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

 

[Arfa Daily]

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

http://www.ozstock.com.au/8108/Super-FREE-Ozstock-Day--CREE-LED-Powered-Torch-with-Adjustable-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

 

[N_Cook]

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

 

[N_Cook]

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.