Hi all,
I know this is not strictly on topic, but this crew seems to know something
about everythig, so here goes:

I am looking to build a "task" lamp (think dentist-type light) that uses
high output white LEDs for a friend who often does
work for extended periods of time in very remote places. I was looking at
the NTE electronics "lightwave" flashlights
http://www.nteinc.com/lightwave/ and they claim that they have circuitry
that makes it possible to run one of the 10
led lights for 24 days, continuously, on 3 D cells.

Any idea how they accomplish that? Most of the high output LEDs I have seen
seem to want to run between 20 and 40 mA
current draw. Given the amp-hour ratings I find for D cells, I don't see how
that would work out. Do they modulate the power to the LEDs
in some way that helps extend the battery life so dramatically?

I looked at just modifing a lightwave flashlight for the task at hand, but
the beam is a bit too wide for what he needs. So I am hoping to
build something with maybe 3 LEDs and appropriate optics to give a fairly
narrow, even beam, mounted on a gooseneck type thing,
with a remote battery pack on a cord.

Any thoughts on the electronics involved? I can handle that part of it, if
I know what I am trying to accomplish.Of course the body
of the thing will be METAL, nicely turned, naturally. (obligatory
metalworking content...)

Thanks for any ideas you can offer.
-AL

In article ,
"AL A." wrote:

Hi all,
I know this is not strictly on topic, but this crew seems to know something
about everythig, so here goes:

I am looking to build a "task" lamp (think dentist-type light) that uses
high output white LEDs for a friend who often does
work for extended periods of time in very remote places. I was looking at
the NTE electronics "lightwave" flashlights
http://www.nteinc.com/lightwave/ and they claim that they have circuitry
that makes it possible to run one of the 10
led lights for 24 days, continuously, on 3 D cells.

Any idea how they accomplish that? Most of the high output LEDs I have seen
seem to want to run between 20 and 40 mA
current draw. Given the amp-hour ratings I find for D cells, I don't see how
that would work out. Do they modulate the power to the LEDs
in some way that helps extend the battery life so dramatically?

I looked at just modifing a lightwave flashlight for the task at hand, but
the beam is a bit too wide for what he needs. So I am hoping to
build something with maybe 3 LEDs and appropriate optics to give a fairly
narrow, even beam, mounted on a gooseneck type thing,
with a remote battery pack on a cord.

Any thoughts on the electronics involved? I can handle that part of it, if
I know what I am trying to accomplish.Of course the body
of the thing will be METAL, nicely turned, naturally. (obligatory
metalworking content...)

Thanks for any ideas you can offer.
-AL



alt.caving may have something, it's been a while tho.
spelunkers are messing with these things too.

If not, I'll be paying attention to answers here :^)


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AL A. wrote:
Hi all,
I know this is not strictly on topic, but this crew seems to know something
about everythig, so here goes:

I am looking to build a "task" lamp (think dentist-type light) that uses
high output white LEDs for a friend who often does
work for extended periods of time in very remote places. I was looking at
the NTE electronics "lightwave" flashlights
http://www.nteinc.com/lightwave/ and they claim that they have circuitry
that makes it possible to run one of the 10
led lights for 24 days, continuously, on 3 D cells.

Any idea how they accomplish that? Most of the high output LEDs I have seen
seem to want to run between 20 and 40 mA
current draw. Given the amp-hour ratings I find for D cells, I don't see how
that would work out. Do they modulate the power to the LEDs
in some way that helps extend the battery life so dramatically?

I looked at just modifing a lightwave flashlight for the task at hand, but
the beam is a bit too wide for what he needs. So I am hoping to
build something with maybe 3 LEDs and appropriate optics to give a fairly
narrow, even beam, mounted on a gooseneck type thing,
with a remote battery pack on a cord.

Any thoughts on the electronics involved? I can handle that part of it, if
I know what I am trying to accomplish.Of course the body
of the thing will be METAL, nicely turned, naturally. (obligatory
metalworking content...)

Thanks for any ideas you can offer.
-AL


AL,

I'm working on a similar project at the moment. Here's what my research
has yielded so far. The majority of ultra bright leds do operate in the
20-40ma range, and the forward voltage is around 1.5-1.7V. If you
arrange the 3 LEDs in series with at least enough cells to provide 4.5V
and an appropriate current-limiting resistor, your current draw will be
20-40ma. If the NTE light is using 7 LEDs with 3 D cells, they are
wiring them in parallel, so the current draw is at least 140ma and the
24 hr figure is highly suspect. If you connect yours in parallel, you
could get by with 2 1.5V cells, but your current draw would triple.

Hope this helps,

Bob

In article , Bob Robinson says...

I'm working on a similar project at the moment. Here's what my research
has yielded so far. The majority of ultra bright leds do operate in the
20-40ma range, and the forward voltage is around 1.5-1.7V.

Agree on the questionable lifespan for the batteries, but
my experience with the white leds is, they're really blue
ones with a bit of yellow phospor. As such, they have
higher (four volt-ish IIRC) turn on voltages.

Jim

==================================================
please reply to:
JRR(zero) at yktvmv (dot) vnet (dot) ibm (dot) com
==================================================

jim rozen writes:

they're really blue
ones with a bit of yellow phospor.

Phosphor? In an LED?

AL A. wrote:
Hi all,
I know this is not strictly on topic, but this crew seems to know something
about everythig, so here goes:

I am looking to build a "task" lamp (think dentist-type light) that uses
high output white LEDs for a friend who often does
work for extended periods of time in very remote places. I was looking at
the NTE electronics "lightwave" flashlights
http://www.nteinc.com/lightwave/ and they claim that they have circuitry
that makes it possible to run one of the 10
led lights for 24 days, continuously, on 3 D cells.

Any idea how they accomplish that? Most of the high output LEDs I have seen
seem to want to run between 20 and 40 mA
current draw. Given the amp-hour ratings I find for D cells, I don't see how
that would work out. Do they modulate the power to the LEDs
in some way that helps extend the battery life so dramatically?

Yes, it's the wonder of marketing.
You time it until you can't see it under an image intensifier in a pitch
black cave.
And then you quote the brightness at the start.

--
http://inquisitor.i.am/ | | Ian Stirling.
---------------------------+-------------------------+--------------------------
All I want is a warm bed, a kind word and unlimited power -- Ashleigh Brilliant.

In article , Richard J Kinch
says...

Phosphor? In an LED?

Yes. The white LEDs that radio shack
sells are really blue led's that excite
a bit of yellowish phosphor on top
of the diode. They have the same
turnon voltage as the blue ones, and
a close inspection of the light
shows that the lens focusses the
blue and yellow light at a slightly
different spot.

Sort of a 'cool white' effect. The
human eye sees blue and yellow light,
and says 'hey, that's white!'

Jim

==================================================
please reply to:
JRR(zero) at yktvmv (dot) vnet (dot) ibm (dot) com
==================================================

In article ,
Jeepers wrote:

alt.caving may have something, it's been a while tho.
spelunkers are messing with these things too.

If not, I'll be paying attention to answers here :^)


One more brand new device :-)

http://www.lumileds.com/pdfs/DS45.PDF

700mA: 70% lumen maintenance at 50,000 hours
1A: 50% lumen maintenance at 20,000 hours


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In article , Ian Stirling says...

And then you quote the brightness at the start.

And they quote it with the absolute max. current
in the diode, such that it will fail shortly
after the intensity measurement is finished!!

Jim

==================================================
please reply to:
JRR(zero) at yktvmv (dot) vnet (dot) ibm (dot) com
==================================================

"AL A." writes:

Hi all,
I know this is not strictly on topic, but this crew seems to know something
about everythig, so here goes:

I am looking to build a "task" lamp (think dentist-type light) that uses
high output white LEDs for a friend who often does
work for extended periods of time in very remote places.

[...]

Thanks for any ideas you can offer.
-AL


Here is a site for a group of cavers that are using white LEDs for headlamps:

http://www.speleogroup.org/attinya.html


HTH,

Jon Etheredge

jim rozen wrote:
In article , Richard J Kinch
says...

Phosphor? In an LED?

Yes. The white LEDs that radio shack
sells are really blue led's that excite
a bit of yellowish phosphor on top
of the diode. They have the same
turnon voltage as the blue ones, and
a close inspection of the light
shows that the lens focusses the
blue and yellow light at a slightly
different spot.

Red too.
The better ones give a pure white spot with no trace of colour variation,
and not too bad red output.

--
http://inquisitor.i.am/ | | Ian Stirling.
---------------------------+-------------------------+--------------------------
Get off a shot FAST, this upsets him long enough to let you make your
second shot perfect. -- Robert A Heinlein.

Hey, Thanks for all of the replies.
I have seen that lots of these do drive the leds at near max current, the
NTE ubits specifically state that
they actually drive them at lower current, and use more leds, to extend
thier life.

The battery life may be a bit of marketing hype, but I do know folks who
use these flashlights and they all say that
the battery life is amazing. I do not know if anyone has actually left
thiers on for 3 weeks, however.

I got a few white leds from electronics goldmine co., 10 mm clear, 4.2v
forward voltage(i think) and
rated at 40 mA max, 2 bucks each. Run at 30mA or so,it is blinding bright
when looked at head on, and they throw
a nice bright sort of soft white light. I have no good way to directly
measure it right now, but I would
put the brightness easily near a 2 AA cell small maglite.

I will fool around a bit more and let you guys know what I find.

As always, still soliciting clever ideas or other info.
Thanks again!
-AL

"AL A." wrote in message
...

The battery life may be a bit of marketing hype, but I do know folks who
use these flashlights and they all say that
the battery life is amazing. I do not know if anyone has actually left
thiers on for 3 weeks, however.

At one of the wholesalers I buy from they sell a 3-D cell light with several
LED's. I don't remember how many. For kicks they turned on a new one, and
left it on 27/7. It was still producing excellent light after four weeks.
After abut eight weeks it was still glowing, but considerably dimmer than at
for weeks. It finally pooped out at around 3 months or so, although the
light output was poor for the last month.

Myself I have a Streamlight, one bulb, 3 - AAAA batteries. I get about six
months of daily use before the light output is low enough that I toss in a
set of batteries. A gent I work with has the same light with lithium
batteries that he has yet to replace after similar use for 2+ years!
I bought a 3 - N cell, 3 LED light the other day, it is about the size of a
mini-maglight. The light output is great, I use it only a couple hours a
week, so I expect batteries to last a year or two.
GReg

On Wed, 15 Oct 2003 14:52:10 -0500, Bob Robinson
wrote:

AL A. wrote:
Hi all,
I know this is not strictly on topic, but this crew seems to know something
about everythig, so here goes:

I am looking to build a "task" lamp (think dentist-type light) that uses
high output white LEDs for a friend who often does
work for extended periods of time in very remote places. I was looking at
the NTE electronics "lightwave" flashlights
http://www.nteinc.com/lightwave/ and they claim that they have circuitry
that makes it possible to run one of the 10
led lights for 24 days, continuously, on 3 D cells.

Any idea how they accomplish that? Most of the high output LEDs I have seen
seem to want to run between 20 and 40 mA
current draw. Given the amp-hour ratings I find for D cells, I don't see how
that would work out. Do they modulate the power to the LEDs
in some way that helps extend the battery life so dramatically?

I looked at just modifing a lightwave flashlight for the task at hand, but
the beam is a bit too wide for what he needs. So I am hoping to
build something with maybe 3 LEDs and appropriate optics to give a fairly
narrow, even beam, mounted on a gooseneck type thing,
with a remote battery pack on a cord.

Any thoughts on the electronics involved? I can handle that part of it, if
I know what I am trying to accomplish.Of course the body
of the thing will be METAL, nicely turned, naturally. (obligatory
metalworking content...)

Thanks for any ideas you can offer.
-AL


AL,

I'm working on a similar project at the moment. Here's what my research
has yielded so far. The majority of ultra bright leds do operate in the
20-40ma range, and the forward voltage is around 1.5-1.7V. If you
arrange the 3 LEDs in series with at least enough cells to provide 4.5V
and an appropriate current-limiting resistor, your current draw will be
20-40ma. If the NTE light is using 7 LEDs with 3 D cells, they are
wiring them in parallel, so the current draw is at least 140ma and the
24 hr figure is highly suspect. If you connect yours in parallel, you
could get by with 2 1.5V cells, but your current draw would triple.

Hope this helps,

Bob

If you folks come up with decent LED flashlights, or plans..the people
over on misc.survivalism would love to have some, as this is a regular
topic of discussion.

Gunner

"You cannot invade the mainland United States. There would be a rifle
behind each blade of grass." --Japanese Admiral Isoroku Yamamoto

On Wed, 15 Oct 2003 19:08:29 GMT, "AL A." pixelated:

Hi all,
I know this is not strictly on topic, but this crew seems to know something
about everythig, so here goes:

I am looking to build a "task" lamp (think dentist-type light) that uses
high output white LEDs for a friend who often does
work for extended periods of time in very remote places. I was looking at
the NTE electronics "lightwave" flashlights
http://www.nteinc.com/lightwave/ and they claim that they have circuitry
that makes it possible to run one of the 10
led lights for 24 days, continuously, on 3 D cells.

Right, at a whopping 2 candlepower output! g

I looked into the LEDs last year and found that many of the
manufacturers who build for the spelunking market put in several
styles of output, with all LEDs on, a few LED on, or one
led on. Some even limited the power to the one LED left on.

Browse the manufacturer sites and get the newest info.
Google for "white LED" and you'll find sources, plans, and
all sorts of other interesting stuff, like LED illumination
for macro shots on digital cameras. I found plans for an
LED ring lamp for my Nikon Coolpix 995 during that search.

-------------------------------
Iguana: The other green meat!
-------------------------------
http://diversify.com Comprehensive Website Development

In article ,
Larry Jaques wrote:

spelunking market

http://www.lumileds.com/


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"Gunner" wrote in message
...
If you folks come up with decent LED flashlights, or plans..the people
over on misc.survivalism would love to have some, as this is a regular
topic of discussion.

What constitutes a "decent LED flashlight", Gunner?
I've build a few that I gave friends in, umm, that work for
the government that they've found useful.

The "white LEDs" are, as was said, blue LEDs with phosphors.
I've fooled with using the base color LEDs combined to give
white light for some efficiency gain but juggling the different
voltages & outputs using surplus components (like I do) is a
pain.

the answer is a PWM circuit that manages the current to the LED - they
didn't say 24 hours a max brightness - the ones for spelunking, for example,
operate at reduced brightness most of the time. Just use a 555, or the CMOS
equivalent with some current feedback
"AL A." wrote in message
...
Hi all,
I know this is not strictly on topic, but this crew seems to know
something
about everythig, so here goes:

I am looking to build a "task" lamp (think dentist-type light) that uses
high output white LEDs for a friend who often does
work for extended periods of time in very remote places. I was looking at
the NTE electronics "lightwave" flashlights
http://www.nteinc.com/lightwave/ and they claim that they have circuitry
that makes it possible to run one of the 10
led lights for 24 days, continuously, on 3 D cells.

Any idea how they accomplish that? Most of the high output LEDs I have
seen
seem to want to run between 20 and 40 mA
current draw. Given the amp-hour ratings I find for D cells, I don't see
how
that would work out. Do they modulate the power to the LEDs
in some way that helps extend the battery life so dramatically?

I looked at just modifing a lightwave flashlight for the task at hand,
but
the beam is a bit too wide for what he needs. So I am hoping to
build something with maybe 3 LEDs and appropriate optics to give a fairly
narrow, even beam, mounted on a gooseneck type thing,
with a remote battery pack on a cord.

Any thoughts on the electronics involved? I can handle that part of it,
if
I know what I am trying to accomplish.Of course the body
of the thing will be METAL, nicely turned, naturally. (obligatory
metalworking content...)

Thanks for any ideas you can offer.
-AL

"jr" == jim rozen writes:

jr In article , Ian Stirling says...
And then you quote the brightness at the start.

jr And they quote it with the absolute max. current
jr in the diode, such that it will fail shortly
jr after the intensity measurement is finished!!

jr Jim

jr ==================================================
jr please reply to:
jr JRR(zero) at yktvmv (dot) vnet (dot) ibm (dot) com
jr ==================================================

It shouldn't be to difficult to build a circuit which would give
essentially constant (and adjustable) brightness for the whole battery
life.

Just charge a capacitor, and dump the charge into the LED when the
voltage exceeds a threshold, then repeat the cycle. You modulate the
intensity by changing the threshold.

For a de luxe version of this scheme, see for example

http://www.fairchildsemi.com/ds/FA/FAN5609.pdf

--
This page intentionally left blank

On Thu, 16 Oct 2003 00:40:57 -0400, "John Keeney"
wrote:


"Gunner" wrote in message
.. .
If you folks come up with decent LED flashlights, or plans..the people
over on misc.survivalism would love to have some, as this is a regular
topic of discussion.

What constitutes a "decent LED flashlight", Gunner?
I've build a few that I gave friends in, umm, that work for
the government that they've found useful.

The "white LEDs" are, as was said, blue LEDs with phosphors.
I've fooled with using the base color LEDs combined to give
white light for some efficiency gain but juggling the different
voltages & outputs using surplus components (like I do) is a
pain.

Hummm lets see.
#1 Maximum brightness over a reasonable circle.
#2 Maximum battery life
#3 maximum ruggedness in the unit
#4 as compact as possible. (and water tight)

#5 batteries must be commonly available
#6 cost

In most cases, color rendition is not a big criteria, though for map
reading its important.
Ive been lead to believe that green is the most efficient color for
average human vision..ie fewer candlepower in green is needed to see
the same distance and with the same resolution, and is almost as good
as red for not knocking out ones nightvision. But green doesnt seem to
me..to focus very well and tends to wash out under dim ambient light.
For me. YMMV. Ive used a few of the blue/whites and they work well for
me 99% of the time, except for washing out my night vision.

A light with a couple heads would be the cats meow..one in blue/white,
one in green, or a head on either end or something similar.

There are a plythora of LED lights on the market, from keychain styles
up to D battery units, and others with lithium$ batteries.

Most of us keep a keychain style handy, though many of them are of
poor quality and are not particularly rugged. Ive busted a couple of
the $10 ones this year alone. Something along the lines of a MiniMag,
double AA battery sized would be damned nice as would a larger
version that uses C batteries.

During an emergency, C batteries are the last to be sold off the
shelves, as few devices use them. Double C battery sized is about
the maximum size that can be held between the teeth for any length of
time while doing something that needs light, or held along side a
handgun or rifle for impromtu illumination of that possum in the
backyard. G I dont wear dentures, so Im good to go..if I
did..smaller is better LOL.

Maximum distance is also nice, though something with a 15ft working
range is ok..longer is better G. If Im walking a trail at night, its
nice to be able to see the path ahead a bit.

A simple sealed push button s switch on the ass end is good, though
"twist the head for on" is probably better due to construction
restraints and ruggedness. A lanyard ring is a virtual requirment.
Like the MiniMags have....

Another light that would be handy..is a small area lantern. Something
you could set down and read by, or cook by etc etc. Fairly limited
range, and either 180 or 360 degrees in illumination arc. If the
power is out and you want to do something..it would be darned nice to
be able to put it on a flat surface, or magneticly stick it to
something. It would be the tits for changing a tire, or working on
your engine, for example. C or D battery would be fine. Perhaps a
sliding cover would be nice, simply close it and drop it into your
glove box or back pack or BoB.

Perhaps others have other criteria that they think would be nice to
have? Or differnt priorities of course.

Gunner
"You cannot invade the mainland United States. There would be a rifle
behind each blade of grass." --Japanese Admiral Isoroku Yamamoto

More on the likes of a buck boost dc-dc converter. Chip makers actually
have specific circuits now that will take 4.5 to 6 volts input and boost
up to 25 to 30 volts at 100ma. Most of the high numbered LED flashlights
use a series-parrallel configuration to get 10 or 15 LEDs with a 50 to
75 ma draw. Thats how they get the long run times.

I use a 4 LED model cheapo that uses 3 AA's. Good for most work in
cabinets and computer chassis. 6 months of normal use and I'm still on
the original set of batteries that it came with it. Normally I would be
changing batteries every month. I think Harbor Freight is now selling them.

Regards

Jim Vrzal
Holiday,Fl.

william_b_noble wrote:
the answer is a PWM circuit that manages the current to the LED - they
didn't say 24 hours a max brightness - the ones for spelunking, for example,
operate at reduced brightness most of the time. Just use a 555, or the CMOS
equivalent with some current feedback
"AL A." wrote in message
...

Hi all,
I know this is not strictly on topic, but this crew seems to know

something

about everythig, so here goes:

I am looking to build a "task" lamp (think dentist-type light) that uses
high output white LEDs for a friend who often does
work for extended periods of time in very remote places. I was looking at
the NTE electronics "lightwave" flashlights
http://www.nteinc.com/lightwave/ and they claim that they have circuitry
that makes it possible to run one of the 10
led lights for 24 days, continuously, on 3 D cells.

Any idea how they accomplish that? Most of the high output LEDs I have

seen

seem to want to run between 20 and 40 mA
current draw. Given the amp-hour ratings I find for D cells, I don't see

how

that would work out. Do they modulate the power to the LEDs
in some way that helps extend the battery life so dramatically?

I looked at just modifing a lightwave flashlight for the task at hand,

but

the beam is a bit too wide for what he needs. So I am hoping to
build something with maybe 3 LEDs and appropriate optics to give a fairly
narrow, even beam, mounted on a gooseneck type thing,
with a remote battery pack on a cord.

Any thoughts on the electronics involved? I can handle that part of it,

if

I know what I am trying to accomplish.Of course the body
of the thing will be METAL, nicely turned, naturally. (obligatory
metalworking content...)

Thanks for any ideas you can offer.
-AL








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http://www.newsfeeds.com - The #1 Newsgroup Service in the World!
-----== Over 100,000 Newsgroups - 19 Different Servers! =-----

Gunner wrote:

Ive been lead to believe that green is the most efficient color for
average human vision..ie fewer candlepower in green is needed to see
the same distance and with the same resolution, and is almost as good
as red for not knocking out ones nightvision. But green doesnt seem to
me..to focus very well and tends to wash out under dim ambient light.

It's not going to give you very good contrast in nature, either; too much
green stuff out there.

Most of us keep a keychain style handy, though many of them are of
poor quality and are not particularly rugged. Ive busted a couple of
the $10 ones this year alone. Something along the lines of a MiniMag,
double AA battery sized would be damned nice as would a larger
version that uses C batteries.

Try the new line from http://www.PALight.com
I've had a bit of durability trouble with early models, but they seem to
have taken my suggestions, as the last set I ordered as gifts (2
Christmases ago and at least one generation of PALights ago, judging from
the current product list) are still working great.

The only potential hassles I see a
a) no off mode - you may want an opaque pouch or similar to hide better
b) 9V batteries - always tape the contacts of your spares before packing
them

(OTOH, the standby light is just about right for hitting the toilet at
night without hurting your eyes, so you might want to try a metal bracket
over the can, and the magnet band for the PAL holding it on target...and
it's a place most of us can find our way to instinctively in the dark)

Double C battery sized is about
the maximum size that can be held between the teeth for any length of
time

The PALights have rubber casings, and the rectangular shape is a lot more
comfortable on teeth, IMO.

Another light that would be handy..is a small area lantern. Something
you could set down and read by, or cook by etc etc. Fairly limited
range, and either 180 or 360 degrees in illumination arc.

For that, I use one of the headlamps that's switchable from red LED to
white LED or Xenon bulb. Good battery life, and if something happens
behind me, I don't have to grab for the light to turn and look.

I also noticed that Wally World has some $8 LED clip/head lights in red or
white that looked like potentially good backups for my current headlamp.

FWIW, I'm not getting paid to shill the PALights, I just find them to be a
pretty responsive company with a product that really exceeds my
expectations as a glovebox or general use low-power flashlight. I always
keep a high-candlepower light available, but for most tasks, I don't even
need the PAL's high beam.

I once used an older PALight Plus (before they had all these fancy models -
all mine are just high/low/slow strobe/standby types) for two weeks of very
heavy use. I had a supply of extra 9V batteries, so I wasn't going easy on
it, either. I was reading quite comfortably for 2-4 hrs a night on low
beam, using standby to keep the bathroom floor clean and high beam
pointed at the ceiling to provide low-level area lighting. I still didn't
change out that (original) battery for almost a month of using it to read
at bus stops afterward. (The light will start changing modes at random
when new battery time hits, but that should take several months of normal
use, or a year or more on standby in the glovebox or BoB) Looks like
they're even shipping Energizers with them now. IIRC, the batteries that
came with mine were off-brand junk and still lasted for months.

Of course, if one of the PALight guys happened to read my posts and send me
a few of the new models to test and review, I wouldn't object too strongly
- the OneStar looks pretty neat, as do the e-Light, magnetic band, and
carrying case, none of which were available when I got my last PAL. How
'bout it guys? There's still time for me to get a couple onto this year's
Christmas list if you convince me soon enough

--
Joe Bramblett, KD5NRH

www.speleo.co.uk


-----= Posted via Newsfeeds.Com, Uncensored Usenet News =-----
http://www.newsfeeds.com - The #1 Newsgroup Service in the World!
-----== Over 100,000 Newsgroups - 19 Different Servers! =-----

I bought the 1w Luxeon star flashlight conversion bulb from The Bright Guy,
(LED CORP IIRC) I am driving it with 2 d alkaline in a mad lite and it gives
WAY more light than the mad lite did. I ordered the 3 AAA luxeon Streamlight
from BOTACH, but they sent the LED/xenon by mistake and I am waiting for the
one I ordered. For information try the candlepower forums, the led museum, or
elektrolumens (sp).

John H.

On Thu, 16 Oct 2003 09:01:33 GMT, Gunner
wrote:

On Thu, 16 Oct 2003 00:40:57 -0400, "John Keeney"
wrote:


"Gunner" wrote in message
. ..
If you folks come up with decent LED flashlights, or plans..the people
over on misc.survivalism would love to have some, as this is a regular
topic of discussion.

What constitutes a "decent LED flashlight", Gunner?
I've build a few that I gave friends in, umm, that work for
the government that they've found useful.

The "white LEDs" are, as was said, blue LEDs with phosphors.
I've fooled with using the base color LEDs combined to give
white light for some efficiency gain but juggling the different
voltages & outputs using surplus components (like I do) is a
pain.

Hummm lets see.
#1 Maximum brightness over a reasonable circle.
#2 Maximum battery life
#3 maximum ruggedness in the unit
#4 as compact as possible. (and water tight)

#5 batteries must be commonly available
#6 cost

CMG Infinity & Ultra Infinity.
1. Ultra Infinity white (reg infinity - colors)
2. 40+ hours
3. thick aluminum case, as thick or thicker than a minimag,
Con: Only waterproof to 10 feet. :-(
4. slightly longer than a "AA" battery
5. "AA" batts. (doesn't get any more common)
6. $12.95 to 16.95 @
http://www.botachtactical.com/cmgequipment.html
7. Hole machined into the end LARGE enough to pass paracord
through.

http://www.cmgequipment.com/products.html

Red: Historically used for preserving night vision, red light,
due to its wavelength, does not cause your pupils to constrict.
As a result, your peripheral vision is greater and your eyes do
not need to re-adjust when the red light is turned off.

White: A white light allows perfect color distinction, but can
cause pupils to dilate, making it more difficult to see outside
of the shining light and causing a longer re-adjustment period
once the light source is extinguished.

Yellow: A yellow light offers benefits of the red and white
lights. While providing reasonable color distinction, it allows
decent night vision. Another benefit of the yellow light is
reduced bounce-back and glare when reading, leading to less eye
strain.

Green: Like red, green light preserves night vision, but offers
additional benefits, including: 1) night vision equipment does
not easily detect green light, 2) ability to distinguish colors
such as yellow and red on a map or chart, and 3) the human eye
detects light in the green spectrum at a lower brightness
compared to a red light.

Blue: Blue is also used to read maps and is preferred by EMT's
and military personnel. Also, this color has a little wider angle
beam than the other colors.

Blue/Green: Similar night vision benefits to the green light and
the blue light. Some users prefer the blue/green light to either
of these.

Infra-Red: For use in conjunction with night vision equipment.
Non visible without the aid of this equipment.

In article , Gunner says...

#1 Maximum brightness over a reasonable circle.
#2 Maximum battery life
#3 maximum ruggedness in the unit
#4 as compact as possible. (and water tight)
#5 batteries must be commonly available
#6 cost

Take a white LED, a small switch, a current
dropping resistor, and solder them on top of
a 9V lithium battery. Tape up with 3M black
electrical tape.

Inexpensive, the Li battery has a *long* shelf
life, they can be totally submerged and still
run, light, compact, and cheap. Cheaper if the
Li battery is replaced with an alkaline, but then
you lose the long shelf life.

A simple sealed push button s switch on the ass end is good, though
"twist the head for on" is probably better due to construction
restraints and ruggedness. A lanyard ring is a virtual requirment.
Like the MiniMags have..

The trouble with the twist-off mag lights is, they turn
on in the pocket. Which results in a very-well illuminated
pocket for a brief period!

Another light that would be handy..is a small area lantern.

For this, at home, I use.... small kerosene lanterns. Fuel
stores indefinitely, they give a lot of light. Fire hazard
high though, obviously. Users have to be indoctrinated.

But the lithium battery LED flashlight is the nuts. Cheap
and lasts forever. I made some of those for my daughter
(we've hiked through the woods near our house at night
using only two of them) and damn if I don't catch her
reading under the covers with them, most nights.

The lack of mechanical contacts, and the use of a proper
mini toggle switch makes them a good deal more reliable
than most commercial lights. Those typically scrimp on
the switch.

Jim

==================================================
please reply to:
JRR(zero) at yktvmv (dot) vnet (dot) ibm (dot) com
==================================================

jim rozen writes:

really blue led's that excite
a bit of yellowish phosphor on top
of the diode.

Quite right. I've had one of those Eddie Bauer flashlights for a while,
and never looked closely at it. It uses the YAG phosphor LEDs. I assumed
it was a red-green-blue triplet.

So this inherits all the color-rendering and perception issues of
fluorescents.

On Wed, 15 Oct 2003 19:08:29 GMT, "AL A." wrote:
I am looking to build a "task" lamp (think dentist-type light) that uses
high output white LEDs for a friend who often does
work for extended periods of time in very remote places. I was looking at
the NTE electronics "lightwave" flashlights
http://www.nteinc.com/lightwave/ and they claim that they have circuitry
that makes it possible to run one of the 10
led lights for 24 days, continuously, on 3 D cells.

Assuming that the batteries are series connected, that's an average
current draw of 2.2 mA for standard alkaline cells.

Any idea how they accomplish that? Most of the high output LEDs I have seen
seem to want to run between 20 and 40 mA
current draw. Given the amp-hour ratings I find for D cells, I don't see how
that would work out. Do they modulate the power to the LEDs
in some way that helps extend the battery life so dramatically?

They must. LEDs don't have the thermal lag that filament type bulbs have.
So they can pulse the LED with a reasonably low duty cycle. If they use
a 5% duty cycle, they can get average current draw down to 2.2 mA while
still producing the same peak output as running continuously at 44 mA.

Of course *average* output is also only 5%, but the eye has persistence,
and is fooled into thinking it is seeing a much brighter light. Some strange
effects would occur for rapidly moving objects, strobing, but for nearly
stationary scenes you'd see about as well as if they were actually drawing
40 mA.

They pulse repetition rate would have to be higher than the persistence
duration of the eye to prevent you from noticing the strobing at ordinary
movement speeds. It probably operates in the kilohertz range.

Gary

On Thu, 16 Oct 2003 09:01:33 GMT, Gunner wrote:

(snip)
During an emergency, C batteries are the last to be sold off the
shelves, as few devices use them. Double C battery sized is about
the maximum size that can be held between the teeth for any length of
time while doing something that needs light, or held along side a
handgun or rifle for impromtu illumination of that possum in the
backyard. G I dont wear dentures, so Im good to go..if I
did..smaller is better LOL.

WalMart also sells a headband for holding a small flashlight that works well. It
has a velcro adjustment, so it's versatile.

Maximum distance is also nice, though something with a 15ft working
range is ok..longer is better G. If Im walking a trail at night, its
nice to be able to see the path ahead a bit.

A simple sealed push button s switch on the ass end is good, though
"twist the head for on" is probably better due to construction
restraints and ruggedness. A lanyard ring is a virtual requirment.
Like the MiniMags have....

Another light that would be handy..is a small area lantern. Something
you could set down and read by, or cook by etc etc. Fairly limited
range, and either 180 or 360 degrees in illumination arc. If the
power is out and you want to do something..it would be darned nice to
be able to put it on a flat surface, or magneticly stick it to
something. It would be the tits for changing a tire, or working on
your engine, for example. C or D battery would be fine. Perhaps a
sliding cover would be nice, simply close it and drop it into your
glove box or back pack or BoB.

http://ledmuseum.home.att.net/ledleft.htm
Select the Energizer Folding LED Lantern. That's the one I have. It's small,
folding(and can be adjusted to different angles), uses AA batteries, and lasts a
LONG time on one set of batteries.

(snip)


It is easier to fight for our principles than to live up to them.-Alfred Adler

Ole-Hjalmar Kristensen wrote:
"jr" == jim rozen writes:

jr In article , Ian Stirling says...
And then you quote the brightness at the start.

jr And they quote it with the absolute max. current
jr in the diode, such that it will fail shortly
jr after the intensity measurement is finished!!

It shouldn't be to difficult to build a circuit which would give
essentially constant (and adjustable) brightness for the whole battery
life.

Just charge a capacitor, and dump the charge into the LED when the
voltage exceeds a threshold, then repeat the cycle. You modulate the
intensity by changing the threshold.

Causing much higher heating due to I^R losses.

For pretty constant, it can get as simple as a transistor and appropriate
variable resistor.
The brightness varies with the battery voltage, rather than with the
battery voltage - LED voltage.

Alternatively, a switched-mode power converter is the way to go.

--
http://inquisitor.i.am/ | | Ian Stirling.
---------------------------+-------------------------+--------------------------
Things a surgeon should never say:
Better save that for the autopsy.

Mustmaker wrote:
I bought the 1w Luxeon star flashlight conversion bulb from The Bright Guy,
(LED CORP IIRC) I am driving it with 2 d alkaline in a mad lite and it gives
WAY more light than the mad lite did. I ordered the 3 AAA luxeon Streamlight
from BOTACH, but they sent the LED/xenon by mistake and I am waiting for the
one I ordered. For information try the candlepower forums, the led museum, or
elektrolumens (sp).

The luxeon star is bright.
I'm currently reterofitting a mini-maglite with one
At the moment I'm polishing the silver reflector, and awaiting delivery of
the sapphire I'm going to use for the lens.

--
http://inquisitor.i.am/ | | Ian Stirling.
---------------------------+-------------------------+--------------------------
Two fish in a tank: one says to the other, "you know how to drive this thing??"

Gary Coffman wrote:

On Wed, 15 Oct 2003 19:08:29 GMT, "AL A." wrote:
I am looking to build a "task" lamp (think dentist-type light) that uses
high output white LEDs for a friend who often does
work for extended periods of time in very remote places. I was looking at
the NTE electronics "lightwave" flashlights
http://www.nteinc.com/lightwave/ and they claim that they have circuitry
that makes it possible to run one of the 10
led lights for 24 days, continuously, on 3 D cells.

Assuming that the batteries are series connected, that's an average
current draw of 2.2 mA for standard alkaline cells.

Any idea how they accomplish that? Most of the high output LEDs I have seen
seem to want to run between 20 and 40 mA
current draw. Given the amp-hour ratings I find for D cells, I don't see how
that would work out. Do they modulate the power to the LEDs
in some way that helps extend the battery life so dramatically?

They must. LEDs don't have the thermal lag that filament type bulbs have.
So they can pulse the LED with a reasonably low duty cycle. If they use
a 5% duty cycle, they can get average current draw down to 2.2 mA while
still producing the same peak output as running continuously at 44 mA.

Of course *average* output is also only 5%, but the eye has persistence,
and is fooled into thinking it is seeing a much brighter light. Some strange
effects would occur for rapidly moving objects, strobing, but for nearly
stationary scenes you'd see about as well as if they were actually drawing
40 mA.

They pulse repetition rate would have to be higher than the persistence
duration of the eye to prevent you from noticing the strobing at ordinary
movement speeds. It probably operates in the kilohertz range.

Gary

Cool reasoning there Gary, I like it, and any "hazards" caused by strobing of
spinning stuff is not very likely, as you probably wouldn't have too much
rotating machinery around places where the only light source was your flashlight.
Except maybe under the hood of a car, where we all know enough to keep the hell
away from the general vicinity of the fan blades when the engine is running.

I remember a public school shop teacher telling me maybe 50 years ago to watch
out for strobing of spinning machinery parts under fluorescent lamps, but I can't
say I've ever noticed the effect. Maybe the phosphors used in today's lamps have
longer persistance than those in the early ones.

Jeff

--
Jeff Wisnia (W1BSV + Brass Rat '57 EE)

"If you can keep smiling when things go wrong, you've thought of someone to place
the blame on."

A friend gave me a Streamlight Clipmate that uses 3 AAAs to light up 3
blue/white leds in a compact light. Unlike most other things, I haven't
taken it apart to see if any electronics are inside. It appears to be a
welded or cyano-glued case made out of tough stuff.

It comes with a head-strap and lanyard and has an integral clip for
attaching the light to a hat visor or pocket flap (nostril, lip, eyelid),
etc.

It's a rotating head twist-on switch design, and appears to be nearly
waterproof but certainly very water resistant with an O-ring in the battery
cover.
It's also offered in a green light version according to the package.
They claim 120 hour battery life.

I picked up a Coleman lantern-style flashlight that I hadn't seen before, at
a flea market. It looks like a short D-size flashlight with an oversized
reflector head.
When the handle is drawn/pulled out of the head, it reveals the internal
clear acrylic tube (similar to a lantern's globe) which allows 360 degree
illumination.
The oversize head acts as a wide lantern base, so it's not as likely to tip
over.

It has 4 AAs in the handle, and seems that it would be a good choice for
adapting to LEDs. The case is fairly rugged and appears to be water
resistant, but it had a crappy switch in it. There is room in the back
portion for a small circuit or an additional switch for your white or green
light options.

WB
....................

"Gunner" wrote in message
news
On Thu, 16 Oct 2003 00:40:57 -0400, "John Keeney"
wrote:


"Gunner" wrote in message
.. .
If you folks come up with decent LED flashlights, or plans..the people
over on misc.survivalism would love to have some, as this is a regular
topic of discussion.

What constitutes a "decent LED flashlight", Gunner?
I've build a few that I gave friends in, umm, that work for
the government that they've found useful.

The "white LEDs" are, as was said, blue LEDs with phosphors.
I've fooled with using the base color LEDs combined to give
white light for some efficiency gain but juggling the different
voltages & outputs using surplus components (like I do) is a
pain.

Hummm lets see.
#1 Maximum brightness over a reasonable circle.
#2 Maximum battery life
#3 maximum ruggedness in the unit
#4 as compact as possible. (and water tight)

#5 batteries must be commonly available
#6 cost

In most cases, color rendition is not a big criteria, though for map
reading its important.
Ive been lead to believe that green is the most efficient color for
average human vision..ie fewer candlepower in green is needed to see
the same distance and with the same resolution, and is almost as good
as red for not knocking out ones nightvision. But green doesnt seem to
me..to focus very well and tends to wash out under dim ambient light.
For me. YMMV. Ive used a few of the blue/whites and they work well for
me 99% of the time, except for washing out my night vision.

A light with a couple heads would be the cats meow..one in blue/white,
one in green, or a head on either end or something similar.

There are a plythora of LED lights on the market, from keychain styles
up to D battery units, and others with lithium$ batteries.

Most of us keep a keychain style handy, though many of them are of
poor quality and are not particularly rugged. Ive busted a couple of
the $10 ones this year alone. Something along the lines of a MiniMag,
double AA battery sized would be damned nice as would a larger
version that uses C batteries.

During an emergency, C batteries are the last to be sold off the
shelves, as few devices use them. Double C battery sized is about
the maximum size that can be held between the teeth for any length of
time while doing something that needs light, or held along side a
handgun or rifle for impromtu illumination of that possum in the
backyard. G I dont wear dentures, so Im good to go..if I
did..smaller is better LOL.

Maximum distance is also nice, though something with a 15ft working
range is ok..longer is better G. If Im walking a trail at night, its
nice to be able to see the path ahead a bit.

A simple sealed push button s switch on the ass end is good, though
"twist the head for on" is probably better due to construction
restraints and ruggedness. A lanyard ring is a virtual requirment.
Like the MiniMags have....

Another light that would be handy..is a small area lantern. Something
you could set down and read by, or cook by etc etc. Fairly limited
range, and either 180 or 360 degrees in illumination arc. If the
power is out and you want to do something..it would be darned nice to
be able to put it on a flat surface, or magneticly stick it to
something. It would be the tits for changing a tire, or working on
your engine, for example. C or D battery would be fine. Perhaps a
sliding cover would be nice, simply close it and drop it into your
glove box or back pack or BoB.

Perhaps others have other criteria that they think would be nice to
have? Or differnt priorities of course.

Gunner
"You cannot invade the mainland United States. There would be a rifle
behind each blade of grass." --Japanese Admiral Isoroku Yamamoto

You can still see strobing on moving parts in flourescent lighting.. a VCR
head will show a strobe effect while playing a tape. Most folks use their
VCRs with the cover on, but service literature often referred to the
strobing as a visual indication that the head/drum speed was correct.

WB
.................

"Jeff Wisnia" wrote in message
...


I remember a public school shop teacher telling me maybe 50 years ago to
watch
out for strobing of spinning machinery parts under fluorescent lamps, but
I can't
say I've ever noticed the effect. Maybe the phosphors used in today's
lamps have
longer persistance than those in the early ones.

Jeff

--
Jeff Wisnia (W1BSV + Brass Rat '57 EE)

"If you can keep smiling when things go wrong, you've thought of someone
to place
the blame on."

LED driver circuits are common these days, all done in a single IC.

Check the usual IC mfrs sites... :- )

_-_-bear

Ole-Hjalmar Kristensen wrote:

"jr" == jim rozen writes:

jr In article , Ian Stirling says...
And then you quote the brightness at the start.

jr And they quote it with the absolute max. current
jr in the diode, such that it will fail shortly
jr after the intensity measurement is finished!!

jr Jim

jr ==================================================
jr please reply to:
jr JRR(zero) at yktvmv (dot) vnet (dot) ibm (dot) com
jr ==================================================

It shouldn't be to difficult to build a circuit which would give
essentially constant (and adjustable) brightness for the whole battery
life.

Just charge a capacitor, and dump the charge into the LED when the
voltage exceeds a threshold, then repeat the cycle. You modulate the
intensity by changing the threshold.

For a de luxe version of this scheme, see for example

http://www.fairchildsemi.com/ds/FA/FAN5609.pdf

--
This page intentionally left blank

http://www.ccrane.com/ccexpedition_1200.asp

Here is one :-)

I have the CCRadio.

Martin
--
Martin Eastburn, Barbara Eastburn
@ home at Lion's Lair with our computer
NRA LOH, NRA Life
NRA Second Amendment Task Force Charter Founder

Gunner wrote:

range is ok..longer is better G. If Im walking a trail at night, its
nice to be able to see the path ahead a bit.

For many years I've used a carbide lamp with a somewhat oversized
reflector. 4 hours operation on a film can of carbide. Good flood at
your feet with a real reach to the spot. I've been experimenting for
years with everything from candle lanterns to an inverter operated
flourescent I built in 1960. Until the LED lights came along there just
wasn't any serious competition to the carbide lamp.

I was recently given a gift of a Princeton Tech Attitude light
http://www.princetontec.com/
Three LEDs, 4 AAA cells, very convenient shape/size, o-ring seal, good
output for walking around. Manufacturer claims "up to 150 hours". MEC
(a Canadian outdoor retailer) claims "more than 50 hours" which I expect
is more realistic. When I run down the alkalines that I have in it, I
may put in Lithiums if they are available in AAA.

Ted

In article , Ted Edwards says...

For many years I've used a carbide lamp with a somewhat oversized
reflector. 4 hours operation on a film can of carbide. Good flood at
your feet with a real reach to the spot.

Those work great - one problem is that folks are not used
to seeing such a strange light. Another is that the open
flame is a bit hazardous, especially indoors.

But those sure are bright. I bought one of the large
supervisor sized ones, with the extra sized reflector.

Jim

==================================================
please reply to:
JRR(zero) at yktvmv (dot) vnet (dot) ibm (dot) com
==================================================

On 16 Oct 2003 09:58:52 GMT, wrote:

snip
(OTOH, the standby light is just about right for hitting the toilet at
night without hurting your eyes,
snip

If you make a lanyard out of fishing line for your LED microlight,
then you can loop the lanyard through a shirt buttonhole. Gravity
causes the light to point in the proper direction, hands-free. Of
course this doesn't work with the lights that only have a mometary
switch.

--
"And I can't describe how I felt when I picked up that rifle,
loaded it into my little car, and drove home. It seemed so
incredibly strange: Sarah Brady, of all people, packing heat."
- source: "A Good Fight", Sarah Brady, chapter 21, page 223
of first edition hardback, ISBN 1-58648-105-3

Ted Edwards wrote:

For many years I've used a carbide lamp with a somewhat oversized
reflector. 4 hours operation on a film can of carbide. Good flood at
your feet with a real reach to the spot. I've been experimenting for
years with everything from candle lanterns to an inverter operated
flourescent I built in 1960. Until the LED lights came along there just
wasn't any serious competition to the carbide lamp.

That depends on your criteria and application. I used to use a carbide
lamp for caving. In terms of the duration-to-weight ratio, it was hard
to beat, and it was the hands-down winner for coolness factor. But a
6-volt halogen lamp put it to shame in terms of light output, as well
as maintenance and ease of operation. I haven't done any caving in a
while and haven't gotten around to trying out an LED lamp yet.

Bert