Making some bike lights for my daughter who rides her bicycle in
traffic in Brooklyn NY.

I'm playing with some red Luxeon LED's, powered from 3 NiMH
rechargable penlight cells.

These suckers are seriously bright. I noted that the one I was
running looked yellow (not red) from a distance of 100 feet -- but
when I looked away for a bit and then looked back they looked red agan
for an instant. WTF, over?

When I walked back I noted that the spill on the table looked red.
Geez, maybe I overloaded my red receptors?

I turned down the current to 30% by soldering in another dropping
resistor. Sure enough, it then looked red at 100 feet.

Wondering why everything looks green now.......

So, what were you doing in the '60s and '70s? Consequences of early
life-choices?


"Don Foreman" wrote in message
...
Making some bike lights for my daughter who rides her bicycle in
traffic in Brooklyn NY.

I'm playing with some red Luxeon LED's, powered from 3 NiMH
rechargable penlight cells.

These suckers are seriously bright. I noted that the one I was
running looked yellow (not red) from a distance of 100 feet -- but
when I looked away for a bit and then looked back they looked red agan
for an instant. WTF, over?

When I walked back I noted that the spill on the table looked red.
Geez, maybe I overloaded my red receptors?

I turned down the current to 30% by soldering in another dropping
resistor. Sure enough, it then looked red at 100 feet.

Wondering why everything looks green now.......

Wrecking my hearing, vision escaped intact -- I think.....

On Sun, 05 Sep 2004 13:15:30 GMT, "Tom Gardner"
wrote:

So, what were you doing in the '60s and '70s? Consequences of early
life-choices?


"Don Foreman" wrote in message
.. .
Making some bike lights for my daughter who rides her bicycle in
traffic in Brooklyn NY.

I'm playing with some red Luxeon LED's, powered from 3 NiMH
rechargable penlight cells.

These suckers are seriously bright. I noted that the one I was
running looked yellow (not red) from a distance of 100 feet -- but
when I looked away for a bit and then looked back they looked red agan
for an instant. WTF, over?

When I walked back I noted that the spill on the table looked red.
Geez, maybe I overloaded my red receptors?

I turned down the current to 30% by soldering in another dropping
resistor. Sure enough, it then looked red at 100 feet.

Wondering why everything looks green now.......

--
"Don Foreman" wrote in message
...
Making some bike lights for my daughter who rides her bicycle in
traffic in Brooklyn NY.

I'm playing with some red Luxeon LED's, powered from 3 NiMH
rechargable penlight cells.

These suckers are seriously bright. I noted that the one I was
running looked yellow (not red) from a distance of 100 feet -- but
when I looked away for a bit and then looked back they looked red agan
for an instant. WTF, over?

When I walked back I noted that the spill on the table looked red.
Geez, maybe I overloaded my red receptors?

I turned down the current to 30% by soldering in another dropping
resistor. Sure enough, it then looked red at 100 feet.

Wondering why everything looks green now.......
The bicycle news groups has discussed LED lights often. On this page and
others are some of the light that I have made.
http://www.billcotton.com/bicycle_electric.htm My first LED light were from
mounting the 15 LED Mag type flashlights that Harbor Freight sells, on my
bicycle. These flashlight get maximum brightness and short life by putting
4+ volts on the LEDs. Another light was made by modifying a one LED head
lamp from HF to accept a 1156 LED replacement bulb and a 12 volt supply.
http://www.billcotton.com/bicycle_el...20LED%20lights

www.billcotton.com
N40° 3.744' W75° 6.180'

Update:

I found some small trailer marker lights at Northern Tool for about 2
bux. I bought one to cut apart for the lens. The Luxeons I bought
are Lambertian emitters. Their radiation pattern is more like a
small filament bulb than a conventional LED. I therefore thought
perhaps a lens devised for use with a small filament bulb might work
well.

It does.

The red Luxeon behind that lens is noticable even in direct sunlight.

I tried it tonight with two 60-watt patio lights and two 100-watt PAR
floods illuminating the backyard to provide some competition like
citylight in Brooklyn will provide. I walked back 100 feet to check
it out from there.

Uh...wow. I think this dog will hunt.


On Sun, 05 Sep 2004 01:48:36 -0500, Don Foreman
wrote:

Making some bike lights for my daughter who rides her bicycle in
traffic in Brooklyn NY.

Nice report, Don! Thanx. Do you know if the manufacturers have data books
out yet on the new hi-power leds?

Bob Swinney
"Don Foreman" wrote in message
...
Update:

I found some small trailer marker lights at Northern Tool for about 2
bux. I bought one to cut apart for the lens. The Luxeons I bought
are Lambertian emitters. Their radiation pattern is more like a
small filament bulb than a conventional LED. I therefore thought
perhaps a lens devised for use with a small filament bulb might work
well.

It does.

The red Luxeon behind that lens is noticable even in direct sunlight.

I tried it tonight with two 60-watt patio lights and two 100-watt PAR
floods illuminating the backyard to provide some competition like
citylight in Brooklyn will provide. I walked back 100 feet to check
it out from there.

Uh...wow. I think this dog will hunt.


On Sun, 05 Sep 2004 01:48:36 -0500, Don Foreman
wrote:

Making some bike lights for my daughter who rides her bicycle in
traffic in Brooklyn NY.

Don't know about books, but datasheets on the Luxeon's are available
for download. The one I'm using is at
http://www.lumileds.com/pdfs/protected/DS25.PDF

There are also 3-watt and 5-watt versions.

http://www.lumileds.com/docs.cfm?docType=3

Jerry and I each made pretty awesome flashlights with 3-watt white
Luxeons.

I prefer to buy the bare emitters rather than the "stars" and machine
(METAL CONTENT) little studs that I epoxy them to with Omegabond
epoxy. I can get them further into a reflector that way.

Osram also offers some bright LED's. Digi-Key even carries them.
They're not as bright as the Luxeons, but a couple of them are close.

These LED's are really fun to play with!




On Tue, 7 Sep 2004 11:32:05 -0500, "Robert Swinney"
wrote:

Nice report, Don! Thanx. Do you know if the manufacturers have data books
out yet on the new hi-power leds?

Bob Swinney
"Don Foreman" wrote in message
.. .
Update:

I found some small trailer marker lights at Northern Tool for about 2
bux. I bought one to cut apart for the lens. The Luxeons I bought
are Lambertian emitters. Their radiation pattern is more like a
small filament bulb than a conventional LED. I therefore thought
perhaps a lens devised for use with a small filament bulb might work
well.

It does.

The red Luxeon behind that lens is noticable even in direct sunlight.

I tried it tonight with two 60-watt patio lights and two 100-watt PAR
floods illuminating the backyard to provide some competition like
citylight in Brooklyn will provide. I walked back 100 feet to check
it out from there.

Uh...wow. I think this dog will hunt.


On Sun, 05 Sep 2004 01:48:36 -0500, Don Foreman
wrote:

Making some bike lights for my daughter who rides her bicycle in
traffic in Brooklyn NY.

Don Foreman wrote:

I prefer to buy the bare emitters rather than the "stars" and machine
(METAL CONTENT) little studs that I epoxy them to with Omegabond
epoxy. I can get them further into a reflector that way.

Is there something special about Omegabond compared to other epoxies?

Ted

What's that Lassie? You say that Don Foreman fell down the old
rec.crafts.metalworking mine and will die if we don't mount a rescue
by Tue, 07 Sep 2004 16:58:57 -0500:

Don't know about books, but datasheets on the Luxeon's are available
for download. The one I'm using is at
http://www.lumileds.com/pdfs/protected/DS25.PDF

There are also 3-watt and 5-watt versions.


Lots of good stuff about LED flashlights he
http://www.candlepowerforums.com/ubb...reads.php?Cat=
--

Dan

It's designed to have high thermal conductivity. Other filled epoxies
might work as well.

"Ted Edwards" wrote in message
...
Don Foreman wrote:

I prefer to buy the bare emitters rather than the "stars" and machine
(METAL CONTENT) little studs that I epoxy them to with Omegabond
epoxy. I can get them further into a reflector that way.

Is there something special about Omegabond compared to other epoxies?

Ted

Don Foreman wrote:

It's designed to have high thermal conductivity. Other filled epoxies
might work as well.

Any idea what the filler is? Aluminum powder maybe?

Ted

Doubt it. It's white in color, with very low electricl conductivity
for use with thermocouples.

Specs for OB-101 at
http://www.omega.com/Temperature/pdf...200_OT-200.pdf

"Ted Edwards" wrote in message
...
Don Foreman wrote:

It's designed to have high thermal conductivity. Other filled epoxies
might work as well.

Any idea what the filler is? Aluminum powder maybe?

Ted

In article , Ted Edwards says...

Don Foreman wrote:

It's designed to have high thermal conductivity. Other filled epoxies
might work as well.

Any idea what the filler is? Aluminum powder maybe?

In some cases (emerson and cummings 2850 epoxy) the filler
is aluminum oxide powder - sapphire. They also make a
1299 epoxy with quartz microspheres as the filler.

I guess if I were doing this and needed high thermal
conductivity I would go with EpoTech's silver-filled
epoxy, like the H20S. Nice stuff.

Jim


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please reply to:
JRR(zero) at pkmfgvm4 (dot) vnet (dot) ibm (dot) com
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The high electrical conductivity of H20S could be a nuisance when mounting
Luxeon emitters -- or thermcouples.
Omegabond 101 works fine here. Temp rise in the joint is about negligible,
it's relatively inexpensive and readily available. There are certainly
other epoxies that would also work well. Luxeon recommends several .

"jim rozen" wrote in message
...
In article , Ted Edwards says...

I guess if I were doing this and needed high thermal
conductivity I would go with EpoTech's silver-filled
epoxy, like the H20S. Nice stuff.

In article , Don Foreman says...

The high electrical conductivity of H20S could be a nuisance when mounting
Luxeon emitters -- or thermcouples.

Right. I mentioned it as an example of a really high
thermal conductive adhesive. Obviously it will short
out whatever electrical contacts is covers.

Jim


--
==================================================
please reply to:
JRR(zero) at pkmfgvm4 (dot) vnet (dot) ibm (dot) com
==================================================