"white" LED's vs. incandescent and halogen lights
me
up the asphalt roads very well. Incandescents, halogens, and sodium
lights do better. There seem to be a lot of oranges and yellows on
the illuminated asphalt surface.
My question is why does it appear this way?
I presume that the yellow-orange-red spectral emissions from the LED's
are weaker than the blues. The blues are voltage induced while the y-
o-r's are secondary from phosphors in the casing. Therefore to help
refine my question,
1. Do the stronger blues in the LED cause the weaker yellow/orange/
reds to be less perceived?
2. Are the yellows and oranges on the asphalt caused by sulfur
compounds or by dust and dirt embedded in the tarry surface?
dlzc
On Dec 4, 3:50 pm, me <dhm_at_best_dot_...@yahoo.com> wrote:
> It's obvious that the mundane "white" LED bicycle
> lights do not light up the asphalt roads very well.
Emitted watts in the fraction or single digit watts.
> Incandescents, halogens, and sodium lights
> do better.
Tens to hundreds of watts.
> There seem to be a lot of oranges and yellows on
> the illuminated asphalt surface.
>
> My question is why does it appear this way?
They are painted that way. People that are not fully color blind can
tell the difference, the paints wear well, and they do not bleach too
fast.
> I presume that the yellow-orange-red spectral
> emissions from the LED's are weaker than the
> blues.
The LEDs probably emit only blue, and have the other colors formed by
scattering. Much like the "white light" from a fluorescent light.
> The blues are voltage induced while the y-
> o-r's are secondary from phosphors in the casing.
> Therefore to help refine my question,
>
> 1. Do the stronger blues in the LED cause the
> weaker yellow/orange/reds to be less perceived?
No, I believe it is a sensitivity in the eye. Blue takes more photons
to fire. Especially for eyes that are triggering mostly rods (black
and white) rather than cones (color).
> 2. Are the yellows and oranges on the asphalt
> caused by sulfur compounds or by dust and dirt
> embedded in the tarry surface?
Probably just scattering losses. Energy is lost, which reduces the
wavelength. And the rod/cone thing.
My two cents.
David A. Smith
Nate Nagel
But if you compare an LED bicycle light to a comparable halogen bicycle
light, you'll prefer the LED. to paraphrase, "there's no substitute for
more power."
nate
(and injection is nice, but I'd rather...)
--
replace "roosters" with "cox" to reply.
http://members.cox.net/njnagel
Mark Thorson
>
> The LEDs probably emit only blue, and have the other colors formed by
> scattering. Much like the "white light" from a fluorescent light.
Scattering? It's fluorescence. A UV LED excites
a set of phosphors that emit white light. That's
what a white LED is.
alie...@gmail.com
> It's obvious that the mundane "white" LED bicycle lights do not light
> up the asphalt roads very well. Incandescents, halogens, and sodium
> lights do better. There seem to be a lot of oranges and yellows on
> the illuminated asphalt surface.
>
> My question is why does it appear this way?
>
> I presume that the yellow-orange-red spectral emissions from the LED's
> are weaker than the blues. The blues are voltage induced while the y-
> o-r's are secondary from phosphors in the casing. Therefore to help
> refine my question,
>
> 1. Do the stronger blues in the LED cause the weaker yellow/orange/
> reds to be less perceived?
"White" LEDs have a strong peak in the blue and a nearly Gaussian
curve centered in the green, extending from the blue-green to the red.
They're kinda weak in the tails. Do a Google Image search for "white
led spectrum" and see for yourself.
The other lamp types you mention are stronger in the red, which the
eye is more sensitive to, particularly at night.
> 2. Are the yellows and oranges on the asphalt caused by sulfur
> compounds or by dust and dirt embedded in the tarry surface?
Asphalt may look black to the casual glance, but reflectance spectra
tell the tale:
http://www.geog.utah.edu/~chen/
Click on the various locations, check out the various surfaces.
Notice for instance "new paving, dark black asphalt, not mixed with
gravel":
http://www.geog.utah.edu/~chen/aspd2.html
is pretty flat, but "old, dirty asphalt paving":
http://www.geog.utah.edu/~chen/aspa.html
rises from the short wavelength (blue) to the long wavelength (red)
end.
...dirty asphalt just reflects red better.
Mark L. Fergerson
Bill Penrose
> 2. Are the yellows and oranges on the asphalt caused by sulfur
> compounds or by dust and dirt embedded in the tarry surface?
I don't see them. I see shades of blue-gray, which is nearly useless
when walking over dark surfaces. Even moonlight is better than white
LEDs.
DB
pm
> On Dec 4, 2:50 pm, me <dhm_at_best_dot_...@yahoo.com> wrote:
>
> > It's obvious that the mundane "white" LED bicycle lights do not light
> > up the asphalt roads very well. Incandescents, halogens, and sodium
> > lights do better. There seem to be a lot of oranges and yellows on
> > the illuminated asphalt surface.
>
> > My question is why does it appear this way?
>
> > I presume that the yellow-orange-red spectral emissions from the LED's
> > are weaker than the blues. The blues are voltage induced while the y-
> > o-r's are secondary from phosphors in the casing. Therefore to help
> > refine my question,
>
> > 1. Do the stronger blues in the LED cause the weaker yellow/orange/
> > reds to be less perceived?
>
> "White" LEDs have a strong peak in the blue and a nearly Gaussian
> curve centered in the green, extending from the blue-green to the red.
> They're kinda weak in the tails. Do a Google Image search for "white
> led spectrum" and see for yourself.
>
> The other lamp types you mention are stronger in the red, which the
> eye is more sensitive to, particularly at night.
Red map lights are used to preserve dark adaptation because rods _do
not_ respond to them. Rods are most sensitive somewhere in the blue-
green. Do a google image search on "rod sensitivity," etc. Combine
with your previous google image search and you will find that the peak
sensitivity for rods coincides with the "dip" in the typical white LED
spectrum.
-pm
Chalo
>
> It's obvious that the mundane "white" LED bicycle lights do not light
> up the asphalt roads very well. Incandescents, halogens, and sodium
> lights do better.
"Mundane" 5mm white LEDs are very low-powered-- typically .07 watts
each-- with poor color rendition. Often, these are overdriven at
around 0.2W to squeeze a bit more light out of them, but this has the
side effect of pushing their color balance farther into the blue
range.
Quality high-flux LEDs like Luxeon, Cree, or Seoul Semiconductor
emitters of nominally 1W or more are not only very bright, but also
very reasonable in their color balance. DiNotte, Niterider, Light &
Motion, Cygolite, Busch & Mueller, and other reputable manufacturers
use high performance, color graded LEDs in their better lights. The
results are categorically better than incandescents (halogen, krypton,
etc.) of similar power.
Generic 5mm white LEDs cost a few cents each at the wholesale level.
They are excellent in terms of cost-effectiveness and power
efficiency. But if you want to see things rather than just be seen by
other road users, you'll need either lots of them, or else better
quality lighting.
Chalo
alie...@gmail.com
The ~430 nm rod peak (beware line wrap):
is a bit offset from the LED dip at 475 nm.
http://www.mvlc.info/images/photos/led/spectral3.jpg
Also, I should have been clearer; cones are more sensitive to red
than to blue.
IMO though WRT the OP's question the deal-breaker is the greater
reflectivity of asphalt in the red independent of light intensity;
illuminated by incandescent etc. lamps it has red-orangish highlights
as the OP says, but under LED illumination it's just black.
There's also the time factor:
http://www.phys.ufl.edu/~avery/course/3400/vision/dark_adaptation.gif
If one doesn't ride long enough to get dark-adapted, the greater
sensitivity of the rods doesn't come into play.
Anyway, isn't the point of a headlight partly to get the rider's
vision out of the scotopic and at least into the mesopic regime?
Personally I have no problem with bluish LEDs while night biking. To
me it doesn't look "wrong", just different.
Mark L. Fergerson
Brendan Gillatt
Hash: SHA1
dlzc wrote:
> Dear me:
>
> On Dec 4, 3:50 pm, me <dhm_at_best_dot_...@yahoo.com> wrote:
>> It's obvious that the mundane "white" LED bicycle
>> lights do not light up the asphalt roads very well.
>
> Emitted watts in the fraction or single digit watts.
>
>> Incandescents, halogens, and sodium lights
>> do better.
>
> Tens to hundreds of watts.
That is an unfair comparison--the _light_ power output of a halogen bulb
is much less than a modern LED for the same electrical power input.
- --
Brendan Gillatt | GPG Key: 0xBF6A0D94
brendan {a} brendangillatt (dot) co (dot) uk
http://www.brendangillatt.co.uk
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Mr. Benn
news:7dqdnRJKOqR5_ofW...@pipex.net:
> -----BEGIN PGP SIGNED MESSAGE-----
> Hash: SHA1
>
> dlzc wrote:
>> Dear me:
>>
>> On Dec 4, 3:50 pm, me <dhm_at_best_dot_...@yahoo.com> wrote:
>>> It's obvious that the mundane "white" LED bicycle
>>> lights do not light up the asphalt roads very well.
>>
>> Emitted watts in the fraction or single digit watts.
>>
>>> Incandescents, halogens, and sodium lights
>>> do better.
>>
>> Tens to hundreds of watts.
>
> That is an unfair comparison--the _light_ power output of a halogen bulb
> is much less than a modern LED for the same electrical power input.
>
The latest LEDs from Cree now produce more than twice the amount of light
that a compact fluorescent tube (CFT - otherwise know as an energy-saving
lamp) produces for the same amount of electrical power. CFTs produce
around 3-4 times the light of a halogen lamp.
Androcles
"Mr. Benn" <%%@invalid.invalid> wrote in message
news:hfdslf$ghr$1...@news.eternal-september.org...
The latest fireflies from Nature now produce more than a million times the
amount
of light that a compact LED produces for even less electrical power.
dlzc
On Dec 5, 6:45 am, Brendan Gillatt
<brendanREMOVET...@brendanREMOVETHISgillatt.co.uk> wrote:
> -----BEGIN PGP SIGNED MESSAGE-----
> Hash: SHA1
>
> dlzc wrote:
> > Dear me:
>
> > On Dec 4, 3:50 pm, me <dhm_at_best_dot_...@yahoo.com> wrote:
> >> It's obvious that the mundane "white" LED bicycle
> >> lights do not light up the asphalt roads very well.
>
> > Emitted watts in the fraction or single digit watts.
>
> >> Incandescents, halogens, and sodium lights
> >> do better.
>
> > Tens to hundreds of watts.
>
> That is an unfair comparison--the _light_ power
> output of a halogen bulb is much less than a modern
> LED for the same electrical power input.
How is that an *unfair* comparison? The LED energy goes nearly
straight to making light, so you can get light from smaller
batteries. The other technologies get a subset of mass to a "natural"
emission temperature, so there is significant heat storage (lost at
end-of-cycle), and heat losses while operating.
You can get more light from a halogen (etc) source, because you don't
have to construct it out of unitary cells of "fixed" output. You just
need a bigger battery...
Not unfair, just physics.
David A. Smith
Brendan Gillatt
Hash: SHA1
dlzc wrote:
> How is that an *unfair* comparison? The LED energy goes nearly
> straight to making light, so you can get light from smaller
> batteries. The other technologies get a subset of mass to a "natural"
> emission temperature, so there is significant heat storage (lost at
> end-of-cycle), and heat losses while operating.
Because you are saying that LED lights emit power in the "fraction or
single digit watts" and that "Incandescents, halogens, and sodium lights"
emit with "Tens to hundreds of watts". This is only true if you supply
the former with a smaller amount of electrical energy than the later.
Hence it is an unfair comparison.
> You can get more light from a halogen (etc) source, because you don't
> have to construct it out of unitary cells of "fixed" output. You just
> need a bigger battery...
>
Huh?
You can make an LED driver of close to 90% efficiency with inputs above
and/or below the battery voltage. There is no need for unitary cells of
fixed output.
- --
Brendan Gillatt | GPG Key: 0xBF6A0D94
brendan {a} brendangillatt (dot) co (dot) uk
http://www.brendangillatt.co.uk
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Nate Nagel
Do they come in a dynohub model? :/
nate
pm
>
> is a bit offset from the LED dip at 475 nm.
>
> http://www.mvlc.info/images/photos/led/spectral3.jpg
>
> Also, I should have been clearer; cones are more sensitive to red
> than to blue.
Maybe you were thinking cones, but still I don't buy it as an
explanation for perceived LED problems. The yellow phosphor is almost
exactly (and not by accident) where you'd want it to be to maximize
luminous efficiency (the CIE y-bar color matching function and the
yellow phosphor both peaking at about 550 nm)
>
> IMO though WRT the OP's question the deal-breaker is the greater
> reflectivity of asphalt in the red independent of light intensity;
> illuminated by incandescent etc. lamps it has red-orangish highlights
> as the OP says, but under LED illumination it's just black.
I think this is part of the problem for sure.
dlzc
On Dec 5, 10:04 am, Brendan Gillatt
<brendanREMOVET...@brendanREMOVETHISgillatt.co.uk> wrote:
> -----BEGIN PGP SIGNED MESSAGE-----
> Hash: SHA1
>
> dlzcwrote:
> > How is that an *unfair* comparison? The
> > LED energy goes nearly straight to making
> > light, so you can get light from smaller
> > batteries. The other technologies get a
> > subset of mass to a "natural" emission
> > temperature, so there is significant heat
> > storage (lost at end-of-cycle), and heat
> > losses while operating.
>
> Because you are saying that LED lights emit
> power in the "fraction or single digit watts"
> and that "Incandescents, halogens, and
> sodium lights" emit with "Tens to hundreds
> of watts".
I'm talking about power *draw*.
> This is only true if you supply the former with
> a smaller amount of electrical energy than the
> later.
Which is what I was talking about, even though that was absolutely not
clear.
> Hence it is an unfair comparison.
As I wrote it, you are correct.
> > You can get more light from a halogen (etc)
> > source, because you don't have to construct
> > it out of unitary cells of "fixed" output. You just
> > need a bigger battery...
>
> Huh?
LEDs are, in the cheap ones I have seen, makes of small individual
units. Maybe they don't have to be, but they have been so far.
> You can make an LED driver of close to 90%
> efficiency with inputs above and/or below the
> battery voltage. There is no need for unitary
> cells of fixed output.
Yes, thank you. I like LEDs too, in case that was not clear.
David A. Smith
Michael Press
<997b3349-b0fc-4c6f...@g4g2000pri.googlegroups.com>,
"nu...@bid.nes" <alie...@gmail.com> wrote:
> On Dec 4, 2:50 pm, me <dhm_at_best_dot_...@yahoo.com> wrote:
> > It's obvious that the mundane "white" LED bicycle lights do not light
> > up the asphalt roads very well. Incandescents, halogens, and sodium
> > lights do better. There seem to be a lot of oranges and yellows on
> > the illuminated asphalt surface.
> >
> > My question is why does it appear this way?
> >
> > I presume that the yellow-orange-red spectral emissions from the LED's
> > are weaker than the blues. The blues are voltage induced while the y-
> > o-r's are secondary from phosphors in the casing. Therefore to help
> > refine my question,
> >
> > 1. Do the stronger blues in the LED cause the weaker yellow/orange/
> > reds to be less perceived?
>
> "White" LEDs have a strong peak in the blue and a nearly Gaussian
> curve centered in the green, extending from the blue-green to the red.
> They're kinda weak in the tails. Do a Google Image search for "white
> led spectrum" and see for yourself.
>
> The other lamp types you mention are stronger in the red, which the
> eye is more sensitive to, particularly at night.
The human eye is not more sensitive to red.
It's peak sensitivity is ~560 nm---between yellow and green.
--
Michael Press
alie...@gmail.com
> In article
> <997b3349-b0fc-4c6f-bbae-d98a3dcf7...@g4g2000pri.googlegroups.com>,
(sigh)
Read the whole thread.
Mark L. Fergerson
DougC
I'm not certain what's out there now--but as of ~3 years ago, the way to
make a "white" LED was to place a yellow-emitting crystal over a blue
LED. If you studied the spectra emitted, you saw lots of blue, much less
yellow, and nearly none of any other wavelengths. Because of the way
that the blue light is perceived, your mind confuses this as /mostly/
"white".
If you tried to use these white LEDs for high-quality lighting (such as
photography) you would frequently find that they had various ring-shaped
artifacts in the beam, colored either yellow or blue. I've got a cheapie
$12 Cateye 3-AA headlight around somewhere I carry as a backup, that has
a very proiminent center blue spot and yellow edge on the beam.
There may be higher-priced "single" LED setups for cameras now that are
a better balance of white, but for pretty much any flashlights, you
still just get the old blue/yellow.
It is easy to forget--but if you compare a LED flashlight to an
"old-fashioned" incan flashlight, you can see how far off the color
balance of the LED is (in spite of the LED appearing to be much
brighter). The total lack of red wavelengths in the LED is plainly
apparent in a comparison.
~
Peter Cole
> It's obvious that the mundane "white" LED bicycle lights do not light
> up the asphalt roads very well. Incandescents, halogens, and sodium
> lights do better.
That's not at all obvious to me.
_
> In article
> <997b3349-b0fc-4c6f...@g4g2000pri.googlegroups.com>,
> "nu...@bid.nes" <alie...@gmail.com> wrote:
>
>> On Dec 4, 2:50锟絧m, me <dhm_at_best_dot_...@yahoo.com> wrote:
>>> It's obvious that the mundane "white" LED bicycle lights do not light
>>> up the asphalt roads very well. 锟絀ncandescents, halogens, and sodium
>>> lights do better. 锟絋here seem to be a lot of oranges and yellows on
>>> the illuminated asphalt surface.
>>>
>>> My question is why does it appear this way?
>>>
>>> I presume that the yellow-orange-red spectral emissions from the LED's
>>> are weaker than the blues. 锟絋he blues are voltage induced while the y-
>>> o-r's are secondary from phosphors in the casing. 锟絋herefore to help
>>> refine my question,
>>>
>>> 1. 锟紻o the stronger blues in the LED cause the weaker yellow/orange/
>>> reds to be less perceived?
>>
>> "White" LEDs have a strong peak in the blue and a nearly Gaussian
>> curve centered in the green, extending from the blue-green to the red.
>> They're kinda weak in the tails. Do a Google Image search for "white
>> led spectrum" and see for yourself.
>>
>> The other lamp types you mention are stronger in the red, which the
>> eye is more sensitive to, particularly at night.
>
> The human eye is not more sensitive to red.
> It's peak sensitivity is ~560 nm---between yellow and green.
At low levels yes; at higher levels the blue response is a bit higher (it's
possible that anomalous trichromats have different sensitivities as well as
different peaks, but a) they are rare, and b) I doubt the differences are
great).
True night vision is colourless - matching the emitted colour to the most
sensitive portion of the eye can be a factor in that case - but of course
it is a multi-variate problem with competing factors such as luminous
efficiency, battery weight, cost, percentage of
dim-but-not-true-night-vision cycling, see versus be seen, general
construction and reliability, etctera.
Androcles
"Peter Cole" <peter...@verizon.net> wrote in message
news:hfgfrt$9f6$1...@news.eternal-september.org...
Then try it and it will be (unless you happen to be blind).
Not that LED bicycle lights were ever intended to illuminate asphalt,
they merely provide a legally required source of light for oncoming
vehicle drivers to observe. If you want to illuminate asphalt, use more
candlepower.
It's obvious (to anyone with eyes and half a brain) that the "white" LED
bicycle lights do not illuminate asphalt roads very well. Incandescents,
thirty-six
> "Peter Cole" <peter_c...@verizon.net> wrote in message
Are "white" LEDs legally white. As in, a white lamp must be fitted to
the front of the vehicle and a red lamp must (usually) be fitted to
the rear and operational during times of darkness.
Frank Krygowski
> "Peter Cole" <peter_c...@verizon.net> wrote in message
>
> news:hfgfrt$9f6$1...@news.eternal-september.org...
>
> > me wrote:
> >> It's obvious that the mundane "white" LED bicycle lights do not light
> >> up the asphalt roads very well. Incandescents, halogens, and sodium
> >> lights do better.
>
> > That's not at all obvious to me.
>
> Then try it and it will be (unless you happen to be blind).
> they merely provide a legally required source of light for oncoming
> vehicle drivers to observe. If you want to illuminate asphalt, use more
> candlepower.
"Not that LED bicycle lights were ever intended to illuminate
asphalt"? That's thoroughly wrong. For just one example, the LED
headlight at http://www.nabendynamo.de/english/index.html is used by
people riding in all-night competitions on the road.
Read some discussion on LED headlights at http://www.peterwhitecycles.com/schmidt-headlights.asp
or at http://www.blayleys.com/articles/lights/page3.htm
It seems you're about a decade behind times ...
>
> It's obvious (to anyone with eyes and half a brain) that the "white" LED
> bicycle lights do not illuminate asphalt roads very well.
... and more than a little rude, as well.
- Frank Krygowski
Androcles
"thirty-six" <thirt...@live.co.uk> wrote in message
news:8d8e6e8b-0984-4fb8...@p30g2000vbt.googlegroups.com...
==========================================
Yes, they are. If you compare older incandescent car headlights
with later halogen lights one will appear to have a yellow tinge
whilst the other appears bluish. Both are legally white.
http://www.catdiaries.co.uk/images/photography_personal/img_1.jpg
From a legal standpoint you can use a hurricane lamp if you wish,
or even a candle with a glass wind shield. There is no legal requirement
to use an electric light, the law was made before electric lighting
became commonly available.
http://img1.photographersdirect.com/img/15262/wm/pd1068794.jpg
Legally the lights are required so that you can be seen, not for you to
see by; in Britain a high brightness red rear fog lamp is now a legal
requirement.
Androcles
"Frank Krygowski" <frkr...@gmail.com> wrote in message
news:38886938-5bb5-4147...@g1g2000vbr.googlegroups.com...
On Dec 6, 10:38 am, "Androcles" <Headmas...@Hogwarts.physics_q> wrote:
> "Peter Cole" <peter_c...@verizon.net> wrote in message
>
> news:hfgfrt$9f6$1...@news.eternal-september.org...
>
> > me wrote:
> >> It's obvious that the mundane "white" LED bicycle lights do not light
> >> up the asphalt roads very well. Incandescents, halogens, and sodium
> >> lights do better.
>
> > That's not at all obvious to me.
>
> Then try it and it will be (unless you happen to be blind).
> LED bicycle lights were ever intended to illuminate asphalt,
> they merely provide a legally required source of light for oncoming
> vehicle drivers to observe. If you want to illuminate asphalt, use more
> candlepower.
"Not that LED bicycle lights were ever intended to illuminate
asphalt"? That's thoroughly wrong. For just one example, the LED
headlight at http://www.nabendynamo.de/english/index.html is used by
people riding in all-night competitions on the road.
================================================
Listen up, dim bulb, if you want to illuminate asphalt then use more
candlepower, it's that fuckin' simple.
Read some discussion on LED headlights at
http://www.peterwhitecycles.com/schmidt-headlights.asp
or at http://www.blayleys.com/articles/lights/page3.htm
It seems you're about a decade behind times ...
>
> It's obvious (to anyone with eyes and half a brain) that the "white" LED
> bicycle lights do not illuminate asphalt roads very well.
... and more than a little rude, as well.
=============================================
As are you.
*plonk*
Do not reply to this generic message, it was automatically generated;
you have been kill-filed, either for being boringly stupid, repetitive,
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Boringly stupid is the most common cause of kill-filing, but because
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damnly my frank, I don't give a dear. Have a nice day and fuck off.
Just zis Guy, you know?
<Headm...@Hogwarts.physics_q> wrote:
>It's obvious (to anyone with eyes and half a brain) that the "white" LED
>bicycle lights do not illuminate asphalt roads very well. Incandescents,
>halogens, and sodium lights do better.
Ah, a citation to the International Journal of Because I Said So.
Always the most compelling of arguments, so much better than Andreas
Oehler's much more time-consuming approach of actually testing them
and posting the results.
Guy
--
http://www.chapmancentral.co.uk/urc
GPG public key at http://www.chapmancentral.co.uk/pgp-public-key.txt
Androcles
"Just zis Guy, you know?" <guy.c...@spamcop.net> wrote in message
news:s4pnh5t3nag8pfo74...@4ax.com...
> On Sun, 6 Dec 2009 15:38:24 -0000, "Androcles"
> <Headm...@Hogwarts.physics_q> wrote:
>
>>It's obvious (to anyone with eyes and half a brain) that the "white" LED
>>bicycle lights do not illuminate asphalt roads very well. Incandescents,
>>halogens, and sodium lights do better.
>
Chapman says so.
You were careful to snip
"Then try it and it will be [obvious] (unless you happen to be blind)" to
show
your bias and prejudice, weren't you, fuckhead?
Just zis Guy, you know?
<Headm...@Hogwarts.physics_q> wrote:
>You were careful to snip
>"Then try it and it will be [obvious] (unless you happen to be blind)" to
>show
>your bias and prejudice, weren't you, fuckhead?
You set followups to your home group, alt.morons. I guess that your
fellow morons must find this intrusive so I set the groups back to the
right place. No, I didn't snip anything meaningful, the appeal to
what is "obvious" seems to me to be highly questionable with the
current generation of LED headlights, which produce a bright
blue-white light which seems to light up blacktop just fine. The
yellow of sodium vapour lamps is, I believe, more about cutting
through fog and mist than about illuminating blacktop.
Tom Keats
Anything that lights-up the road surface enough to cast
shadows to create a 3-D effect so one can see well enough
to ride by is good.
Anything that casts enough of a spot on the street ahead
while announcing one's arrival into an intersection is
also good.
So many riders want to totally dump the onus of care on
drivers, rather than assume responsibility for their own
conduct.
There's a big difference between /having/ some sort of
bike light, and actually /using/ it beyond just switching
it on.
Riding in the darkness of night is not an endeavour to
be undertaken by the stupid.
Or. it is, but not for long.
--
Nothing is safe from me.
I'm really at:
tkeats curlicue vcn dot bc dot ca
Michael Press
<262ae817-5c88-489b...@x5g2000prf.googlegroups.com>,
"nu...@bid.nes" <alie...@gmail.com> wrote:
I read it. The human eye is not more sensitive to red.
--
Michael Press
Peter Cole
> It's obvious (to anyone with eyes and half a brain) that the "white" LED
> bicycle lights do not illuminate asphalt roads very well. Incandescents,
> halogens, and sodium lights do better.
A whole brain gives a different impression.
Androcles
Ok, so you hallucinate that a pissy little Xmas tree light
is brighter than a sodium or mercury vapour street light.
Get your local authority to install them on lamp posts.
Just zis Guy, you know?
<Headm...@Hogwarts.physics_q> wrote:
>*plonk*
Seems that "Androcles" is a total plonker. Who'd have thought it.
Chalo
>
> It is easy to forget--but if you compare a LED flashlight to an
> "old-fashioned" incan flashlight, you can see how far off the color
> balance of the LED is (in spite of the LED appearing to be much
> brighter).
What I think is, "wow, I used to consider this pitiful yellow Maglite
to be pretty badass."
Thinking back to the bad old days, I remember using very expensive
indoor photography light bulbs with lifespans measured in tens of
hours. They were overdriven in the attempt to raise their color
temperature a little bit above dull yellow. And the attempt was only
partly successful, considering that you still had to use color-biased
"Tungsten" film to get naturalistic color rendering. A continuous
spectrum is not the same thing as a good one! It has to be pretty
continuous and pretty white, too.
I use 3500-4100K compact fluorescents all over my house now, and the
occasional incandescent bulb is a living reminder of a time when
streetlights were green and house lights were miserable.
Chalo
Chalo
Same here. Watt for watt, there is no comparison. LEDs, even cheap
'n crappy 5mm LEDs that are overdriven and color-distorted, put out so
much more light for a given amount of juice compared to incandescents
that you might as well compare them to cigarette lighters or
glowsticks.
Chalo
Frank Krygowski
Careful, Chalo! "Androcles" may plonk you. And I'm sure that will
bother you just as much as it bothered me! ;-)
- Frank Krygowski
Keitht
filters in - red and green - to pick out some of the lumpy bits?
--
Its never too late to reinvent the bicycle
Keitht
> "thirty-six" <thirt...@live.co.uk> wrote in message
> Are "white" LEDs legally white. As in, a white lamp must be fitted to
> the front of the vehicle and a red lamp must (usually) be fitted to
> the rear and operational during times of darkness.
> ==========================================
> Yes, they are. If you compare older incandescent car headlights
> with later halogen lights one will appear to have a yellow tinge
> whilst the other appears bluish. Both are legally white.
> http://www.catdiaries.co.uk/images/photography_personal/img_1.jpg
> From a legal standpoint you can use a hurricane lamp if you wish,
> or even a candle with a glass wind shield. There is no legal requirement
> to use an electric light, the law was made before electric lighting
> became commonly available.
> http://img1.photographersdirect.com/img/15262/wm/pd1068794.jpg
> Legally the lights are required so that you can be seen, not for you to
> see by; in Britain a high brightness red rear fog lamp is now a legal
> requirement.
>
>
>
>
That was the issue all along - that it's based on power not brightness.
It's how you can have incredibly bright car headlights based on halogen
and other metals and really shite yellowish bulbs that are still bits of
coiled wire - both are perfectly legal as the power consumption is the
same.
LED's gave us the chance to 'shine', the battery life is a bonus.
Peter Clinch
> It's obvious that the mundane "white" LED bicycle lights do not light
> up the asphalt roads very well. Incandescents, halogens, and sodium
> lights do better.
Oh. Last week I had the chance to compare a well respected halogen lamp
(BuM Lumotec Oval) to a well respected LED lamp (BuM IQ Fly) on the same
(unlit, asphalt) road at the same time, both running from dynoubs on
side by side bikes, and the IQ Fly did a damn site better job of
lighting it up.
So obvious to some, perhaps, but not me.
Pete.
--
Peter Clinch Medical Physics IT Officer
Tel 44 1382 660111 ext. 33637 Univ. of Dundee, Ninewells Hospital
Fax 44 1382 640177 Dundee DD1 9SY Scotland UK
net p.j.c...@dundee.ac.uk http://www.dundee.ac.uk/~pjclinch/
Androcles
"Keitht" <KeithT> wrote in message
news:yLidnVlXK8Y6JIHW...@bt.com...
What you need is a white one on a bicycle to meet legal requirements,
and a cluster of 1 red, 1 green and one blue LED would meet that
requirement. Put one of these on your handlebars and entertain
the oncoming drivers.
http://gadgetwise.blogs.nytimes.com/2009/06/11/whats-an-led-tv/
Androcles
"Chalo" <chalo....@gmail.com> wrote in message
news:b51d3d37-d9d9-4aa8...@p32g2000vbi.googlegroups.com...
Chalo
========================================
How did "watt for watt" come into it?
The comparison is LED for incandescent/gas discharge lamps,
not watt-for-watt.
Nobody is denying LEDs are more efficient, but they do not
illuminate asphalt roads as well as sodium street lights - OBVIOUSLY.
nailer
Androcles
"Keitht" <KeithT> wrote in message
a legal definition then it should be in lumens, not watts, and wavelength,
not colour. But then, it probably is defined that way. I'm not that much
of a legal eagle to want to find out.
http://en.wikipedia.org/wiki/Luminous_efficacy
thirty-six
> Androcles wrote:
> > "thirty-six" <thirty-...@live.co.uk> wrote in message
I don't think there is any point in attempting to compete with car
headlights. If we can obtain similar brightness and size to a 24W
incandescent (not legal) reversing lamp then we have all the
visibility requirements we need. Experience shows this is way in
excess of what we need to illuminate the road effevtively. I have a
flood type car headlamp reflector of around 3" and would like to see
this with an LED driver fitted if possible.
Frank Krygowski
> "Chalo" <chalo.col...@gmail.com> wrote in message
Ah! And sodium street lights do not light the pavement as well as
aircraft landing lights? And aircraft landing lights do not light the
pavement as well as nuclear explosions?
Meanwhile, in the real world, lights for vehicles (especially
bicycles) will continue to be limited by things like power input, size
and weight. We'll not be carrying our own sodium street lights with
us.
Perhaps "Androcles" didn't realize that.
- Frank Krygowski
Clive George
>> How did "watt for watt" come into it?
>> The comparison is LED for incandescent/gas discharge lamps,
>> not watt-for-watt.
>> Nobody is denying LEDs are more efficient, but they do not
>> illuminate asphalt roads as well as sodium street lights - OBVIOUSLY.
>
>Ah! And sodium street lights do not light the pavement as well as
>aircraft landing lights? And aircraft landing lights do not light the
>pavement as well as nuclear explosions?
>
>Meanwhile, in the real world, lights for vehicles (especially
>bicycles) will continue to be limited by things like power input, size
>and weight. We'll not be carrying our own sodium street lights with
>us.
>
>Perhaps "Androcles" didn't realize that.
Androcles also apparently doesn't realise that LED street lamps are
happening.
Androcles
"Clive George" <cl...@xxxx-x.fsnet.co.uk> wrote in message
news:fomdnZjWDMa_34DW...@brightview.co.uk...
lights.
Perhaps "Frank Krygowski" didn't realise that.
Clive George apparently doesn't realise in the real world
change doesn't happen overnight.
Frank Krygowski
> "Clive George" <cl...@xxxx-x.fsnet.co.uk> wrote in message
>
> news:fomdnZjWDMa_34DW...@brightview.co.uk...
>
> >news:7d598d29-9213-40ae...@j14g2000yqm.googlegroups.com...
>
> >>> How did "watt for watt" come into it?
> >>> The comparison is LED for incandescent/gas discharge lamps,
> >>> not watt-for-watt.
> >>> Nobody is denying LEDs are more efficient, but they do not
> >>> illuminate asphalt roads as well as sodium street lights - OBVIOUSLY.
>
> >>Ah! And sodium street lights do not light the pavement as well as
> >>aircraft landing lights? And aircraft landing lights do not light the
> >>pavement as well as nuclear explosions?
>
> >>Meanwhile, in the real world, lights for vehicles (especially
> >>bicycles) will continue to be limited by things like power input, size
> >>and weight. We'll not be carrying our own sodium street lights with
> >>us.
>
> >>Perhaps "Androcles" didn't realize that.
>
> > Androcles also apparently doesn't realise that LED street lamps are
> > happening.
>
> In the real world sodium lamps are still in use and LEDs are xmas tree
> lights.
> Perhaps "Frank Krygowski" didn't realise that.
Hey! I was supposed to be plonked! That's supposed to be a promise
that you won't respond to my posts!
Please uphold that standard - or be recognized as a liar, or a person
of weak resolve. Or both.
- Frank Krygowski
Chalo
>
> Clive George wrote:
> >
> > Frank Krygowski wrote:
> >>
> >> Androcles wrote:
> >>>
> >>> How did "watt for watt" come into it?
> >>> The comparison is LED for incandescent/gas discharge lamps,
> >>> not watt-for-watt.
> >>> Nobody is denying LEDs are more efficient, but they do not
> >>> illuminate asphalt roads as well as sodium street lights - OBVIOUSLY.
> >>
> >>bicycles) will continue to be limited by things like power input, size
> >>and weight. We'll not be carrying our own sodium street lights with
> >>us.
> >
> > happening.
>
> In the real world sodium lamps are still in use and LEDs are xmas tree
> lights.
> Perhaps "Frank Krygowski" didn't realise that.
> Clive George apparently doesn't realise in the real world
> change doesn't happen overnight.
In my real world for the past half dozen years or so, LED flashlights
and bike lights consume at least 1.3 watts each, need heat sinking,
and make at least dozens of lumens (in a pretty decent facsimile of
daylight white).
For my part, I can compare the 2xAA Planet Bike 1200x handlebar-
mounted incandescent headlights I had before, to the Luxeon and Cree
LED versions I converted them to. I have a couple of each now. They
are the same size (because they use the same bodies),
indistinguishable in weight, and they use the same batteries. The LED
versions run longer on a charge; have a much broader, smoother,
brighter, and whiter beam; continue to work well after the batteries
diminish in voltage, have a high and low beam, and can flash
continuously if I want them to.
A pair of AA NiMH rechargeable batteries contains about 5 watt-hours
of energy, and it is inexpensive and easy to substitute if it fails in
an emergency. This energy source allows a headlight to have a very
convenient pocketable shape and size. To reap these benefits, you
have to accept the energy limitation-- which makes a watt-for-watt
comparison of LEDs versus other light sources quite relevant. In my
analysis, quantity of light per watt is the most important measure of
a bicycle light source.
Chalo
Clive George
news:DwbTm.85798$Xc2....@newsfe24.ams2...
>
> "Clive George" <cl...@xxxx-x.fsnet.co.uk> wrote in message
> news:fomdnZjWDMa_34DW...@brightview.co.uk...
>> "Frank Krygowski" <frkr...@gmail.com> wrote in message
>> news:7d598d29-9213-40ae...@j14g2000yqm.googlegroups.com...
>>
>>>> How did "watt for watt" come into it?
>>>> The comparison is LED for incandescent/gas discharge lamps,
>>>> not watt-for-watt.
>>>> Nobody is denying LEDs are more efficient, but they do not
>>>> illuminate asphalt roads as well as sodium street lights - OBVIOUSLY.
>>>
>>>Ah! And sodium street lights do not light the pavement as well as
>>>aircraft landing lights? And aircraft landing lights do not light the
>>>pavement as well as nuclear explosions?
>>>
>>>Meanwhile, in the real world, lights for vehicles (especially
>>>bicycles) will continue to be limited by things like power input, size
>>>and weight. We'll not be carrying our own sodium street lights with
>>>us.
>>>
>>>Perhaps "Androcles" didn't realize that.
>>
>> Androcles also apparently doesn't realise that LED street lamps are
>> happening.
> In the real world sodium lamps are still in use and LEDs are xmas tree
> lights.
It's amusing to see the pompous way you'll plonk people and compare it with
the stupidity which you exhibit to prompt the posts which invoke it.
In the real world LEDs are traffic lights, bike lights, car lights, street
lights. Just because they aren't universal doesn't mean they aren't there,
and aren't growing in number.
> Perhaps "Frank Krygowski" didn't realise that.
> Clive George apparently doesn't realise in the real world
> change doesn't happen overnight.
Dude, _you're_ the one who says sodium street lights are better than LEDs.
You're also apparently the one who has no real life experience of bike
lights, but that bit has been covered already.
<awaits pompous plonking>
Androcles
Dude, the cost of a sodium lamp street light is $70, less than
a bicycle. The cost of a LED street light is $485, more than a bicycle.
You're also apparently the one who has no real life experience of economics.
As requested, here's the plonk.
Androcles
Chalo
===========================================
http://progress-energy.com/custservice/shared/LEDStreetLightTestProjectReport.pdf
Just zis Guy, you know?
> In the real world sodium lamps are still in use and LEDs are xmas tree
> lights.
> Perhaps "Frank Krygowski" didn't realise that.
> Clive George apparently doesn't realise in the real world
> change doesn't happen overnight.
Your real world is stuck in the last millennium. These days you'll
find LEDs in use in a variety of lighting applications, including some
(OEM) automotive lighting applications. The colour temperature of
LEDs is also a close match to that of the highest specification
automotive headlights, the projector type lamps fitted to a lot of
current luxury and sports cars. LEDs are also used in some of the
best and most expensive bicycle headlights on the market.
--
Guy
Chalo
>
> Chalo wrote:
> >
> > A pair of AA NiMH rechargeable batteries contains about 5 watt-hours
> > of energy, and it is inexpensive and easy to substitute if it fails in
> > an emergency. This energy source allows a headlight to have a very
> > convenient pocketable shape and size. To reap these benefits, you
> > have to accept the energy limitation-- which makes a watt-for-watt
> > comparison of LEDs versus other light sources quite relevant. In my
> > analysis, quantity of light per watt is the most important measure of
> > a bicycle light source.
>
> http://progress-energy.com/custservice/shared/LEDStreetLightTestProje...
I don't understand what you are getting at by this. White LED is a
better quality light source than high-pressure sodium, but it is not
categorically more power-efficient. Low-pressure sodium lighting is
more efficient yet, and even worse in light quality.
To my knowledge, there is no form of high-pressure sodium lighting
that can be carried on a bicycle, let alone powered by a pair of AA
cells. However much it may excel in terms of lumens per watt, it does
not qualify as a bicycle light.
Are you suggesting that bicycle lighting should be more predominantly
yellow like street lighting? Note that there are high efficiency,
high flux amber LEDs that operate at full power with less than 3 volts
to the emitter. I have used amber Luxeon LEDs in combination with a
larger number of white Luxeon LEDs for better color rendition in
portable sign lighting. I experimented with adding red LED light as
well, but it did not help significantly for the signs I was
illuminating.
Chalo
Androcles
Chalo
=============================================
$70 a 25-year unit versus $485 a 15-year unit.
As with any fixture, maintenance will still be required for wires, brackets,
knockdowns, adjustments, periodic cleaning, animal damage, pole maintenance,
and potentially earlier fixture replacement (12 - 15 years) vs. today's
replacement cycle of 20-25 years.
If you want to be seen by other road users, display a simple and cheap light
for safety - any old LED will do although the law has a colour requirement,
white front and red rear. If you want to illuminate the environment, whether
by headlights or street lights, ya gotta pay. I'm happy for you to spend
your
money on bicycle lights - don't spend mine on street lights. Which makes a
lumen-for-penny comparison of LEDs versus other light sources far more
relevant than a watt-for-watt comparison.
That's what I'm getting at.
Marc
Clive George
> $70 a 25-year unit versus $485 a 15-year unit.
...
> If you want to illuminate the environment, whether by headlights or street
> lights, ya gotta pay. I'm happy for you to spend your money on bicycle
> lights - don't spend mine on street lights. Which makes a lumen-for-penny
> comparison of LEDs versus other light sources far more relevant than a
> watt-for-watt comparison.
> That's what I'm getting at.
Try doing one, even with the cuttting-edge technology you're using there.
Right now, not taking into account infrastructure costs, if the electricity
costs are factored in it's only slightly in favour of the HPS. But these
lights aren't going to stay at $485 - put them in proper production and that
cost is only going one way.
Do the sums yourself, rather than blustering.
Chalo
>
> Chalo wrote:
> >
> > Androcles wrote:
> >>
> >> http://progress-energy.com/custservice/shared/LEDStreetLightTestProje...
> >
> > I don't understand what you are getting at by this. White LED is a
> > better quality light source than high-pressure sodium, but it is not
> > categorically more power-efficient. Low-pressure sodium lighting is
> > more efficient yet, and even worse in light quality.
> >
> > To my knowledge, there is no form of high-pressure sodium lighting
> > that can be carried on a bicycle, let alone powered by a pair of AA
> > cells. However much it may excel in terms of lumens per watt, it does
> > not qualify as a bicycle light.
> >
> > Are you suggesting that bicycle lighting should be more predominantly
> > yellow like street lighting? Note that there are high efficiency,
> > high flux amber LEDs that operate at full power with less than 3 volts
> > to the emitter. I have used amber Luxeon LEDs in combination with a
> > larger number of white Luxeon LEDs for better color rendition in
> > portable sign lighting. I experimented with adding red LED light as
> > well, but it did not help significantly for the signs I was
> > illuminating.
>
> As with any fixture, maintenance will still be required for wires, brackets,
> knockdowns, adjustments, periodic cleaning, animal damage, pole maintenance,
> and potentially earlier fixture replacement (12 - 15 years) vs. today's
> replacement cycle of 20-25 years.
>
> If you want to be seen by other road users, display a simple and cheap light
> for safety - any old LED will do although the law has a colour requirement,
> white front and red rear. If you want to illuminate the environment, whether
> by headlights or street lights, ya gotta pay. I'm happy for you to spend
> your
> money on bicycle lights - don't spend mine on street lights. Which makes a
> lumen-for-penny comparison of LEDs versus other light sources far more
> relevant than a watt-for-watt comparison.
> That's what I'm getting at.
Just to be clear, are you aware that you're posting to
rec.bicycles.tech, rec.bicycles.misc, and uk.rec.cycling?
And are you aware that everybody else here is talking about on-bike
lighting?
Just curious.
Chalo
P.S.-- There's something wrong with your reply formatting. It's a
hassle to clean it up for you.
Androcles
Just curious.
Chalo
======================================
Yes, I'm aware, but I didn't start the thread. Are you aware
you are cross-posting to sci.physics? Everybody else here
talks about whatever floats their boat; the subject of LEDs
has nothing to do with bicycles.
=======================================
P.S.-- There's something wrong with your reply formatting. It's a
hassle to clean it up for you.
=======================================
Wrong, there is nothing wrong with my formatting, the hassle is all
Google breaking into usenet (which was here long before Google).
http://en.wikipedia.org/wiki/Usenet
If you don't like Google causing a hassle I'd suggest you stay
out of usenet and stick to Google Groups.
Are you aware you have a gmail address and I don't have any
trouble when writing to normal people?
Androcles
"Marc" <initial...@btintenret.com> wrote in message
news:A5qdnSXa38YN-4DW...@bt.com...
You can fuck off too, one line responses are most uninteresting, three
word responses even more so.
Nate Nagel
Indeed. And those of us with hub dynamos are limited to 3W for our
lights, so lumens per watt is by FAR the most important criterion.
Lumens per dollar is also important, but many night cyclists are willing
to spend whatever it takes to be able to see well at night. Generally,
with a hub dynamo, LEDs are really the only sensible choice, although if
you're willing to lug a battery pack that opens up other options.
nate
--
replace "roosters" with "cox" to reply.
http://members.cox.net/njnagel
Tom Sherman °_°
>> Not very well.
>
> You can fuck off too, one line responses are most uninteresting, three
> word responses even more so.
> *plonk*
Hey, can I get kill-filed too?
--
Tom Sherman - 42.435731,-83.985007
I am a vehicular cyclist.
Androcles
"Tom Sherman �_�" <twsherm...@THISsouthslope.net> wrote in message
news:hfk4ga$vlv$1...@news.eternal-september.org...
> Androcles WHO? ANONYMOUSLY SNIPES:
>> "Marc" <initial...@btintenret.com> wrote in message
>> news:A5qdnSXa38YN-4DW...@bt.com...
>>> [...]
>>> Not very well.
>>
>> You can fuck off too, one line responses are most uninteresting, three
>> word responses even more so.
>> *plonk*
>> [...]
>
> Hey, can I get kill-filed too?
Yes. No problem.
Frank Krygowski
> "Tom Sherman °_°" <twshermanREM...@THISsouthslope.net> wrote :
>
> > Hey, can I get kill-filed too?
>
> Yes. No problem.
> *plonk*
Don't believe him, Tom. His supposed plonks are just a way to
discourage rebuttals he can't answer. He still reads your posts, and
sometimes can't stop himself from responding.
I don't mind him reading, but the responses are as dumb and annoying
as a six-year-old at the symphony.
Bears more than a trace of jutishness, I'd say.
- Frank Krygowski
Peter Cole
> Indeed. And those of us with hub dynamos are limited to 3W for our
> lights, so lumens per watt is by FAR the most important criterion.
> Lumens per dollar is also important, but many night cyclists are willing
> to spend whatever it takes to be able to see well at night. Generally,
> with a hub dynamo, LEDs are really the only sensible choice, although if
> you're willing to lug a battery pack that opens up other options.
The efficiency of LED's means you don't need much of a battery pack, and
continuing developments in battery technologies means that pack is light
and cheap and durable. At this point LED's have pretty much killed off
the "other options".
Helmut Springer
> And those of us with hub dynamos are limited to 3W for our lights,
Actually not. The hub dynamo will happily deliver more than that,
given sufficient speed and suitable lights, e.g. two LED headlights
in series.
> Generally, with a hub dynamo, LEDs are really the only sensible
> choice,
Yes. Then you see the first high end cars on the market with pure
LED frontlights...LED will take over.
--
MfG/Best regards
helmut springer panta rhei
Martin Brown
> me wrote:
>> It's obvious that the mundane "white" LED bicycle lights do not light
>> up the asphalt roads very well. Incandescents, halogens, and sodium
>> lights do better.
>
> (BuM Lumotec Oval) to a well respected LED lamp (BuM IQ Fly) on the same
> (unlit, asphalt) road at the same time, both running from dynoubs on
> side by side bikes, and the IQ Fly did a damn site better job of
> lighting it up.
>
> So obvious to some, perhaps, but not me.
For the same power consumption an LED based unit should be way brighter
than an ordinary incandescent bulb and a fair bit brighter than a
halogen. Lumens per watt pretty much clinches it. The trade is that you
get better battery life and the same amount of light with the LED device
- at least if the designer knows what he is doing. It is an even better
win for the red tail light since red LEDs are pure red emitters with no
need to filter them and the package is self collimated by design.
The problem is that you don't often get single white LEDs at much beyond
1W total power dissipation so some devices are based on specsmanship.
BTW I have never seen sodium lights fitted to bicycles - do they really
do that in the USA?
Regards,
Martin Brown
Frank Krygowski
wrote:
>
>
> BTW I have never seen sodium lights fitted to bicycles - do they really
> do that in the USA?
They do that only in Androcles' mind. Or more accurately, only in his
deviant arguments. Even he doesn't really believe that.
- Frank Krygowski
Clive George
news:IauTm.3191$ha3....@newsfe19.iad...
> The problem is that you don't often get single white LEDs at much beyond
> 1W total power dissipation so some devices are based on specsmanship.
LEDs bigger than that are well into the mainstream now. B+M's LEDs are 3-4W
single white, and the MTB lights will be bigger than that - some use
multiple LEDs, but they're still quite powerful. ISTR 3W luxeons coming
along several years ago, and the industry has been moving very quickly since
then.
The streetlights mentioned in that test are 167W units with 60 LEDs in
each - and I'd expect them to be quite conservative about lifetime in that
application (they're aiming for 50,000 hours plus at a guess).
N8N
> Mon, 07 Dec 2009 17:04:36 -0500, Nate Nagel:
>
> >And those of us with hub dynamos are limited to 3W for our
> >lights,
>
> dynamos? Have you tried two LED-headlights connected in series?
Not yet, but I may. I do have a Shimano hub dynamo and an IQ Cyo on
one of my bikes, but have never gone so far as to hook up an ammeter
while riding (although that is exactly the sort of thing that I would
do, mind you)
little bugger was so expensive that hooking up *two* of them is not
really an option at this point...
>
> Up to 8 Watt are no problem to get from a hub dynamo at higher speed.
>
> >so lumens per watt is by FAR the most important criterion.
>
> In any case. Efficiency is the key figure on every aspect on a bicycle.
Sure, but it is less of one (although still important) in some of the
stationary apps that were also being discussed.
nate
Just zis Guy, you know?
<frkr...@gmail.com> wrote:
>> BTW I have never seen sodium lights fitted to bicycles - do they really
>> do that in the USA?
>They do that only in Androcles' mind. Or more accurately, only in his
>deviant arguments. Even he doesn't really believe that.
I wonder if he's channeling Steven Scharf?
Guy
--
http://www.chapmancentral.co.uk/urc
GPG public key at http://www.chapmancentral.co.uk/pgp-public-key.txt
Ron Peterson
> The latest fireflies from Nature now produce more than a million times the
> amount
> of light that a compact LED produces for even less electrical power.
White LEDs can have an efficiency of 22% currently compared to a
maximum possible efficiency for white light of 37%, fireflies are only
96% efficient.
--
Ron
Androcles
"Ron Peterson" <r...@shell.core.com> wrote in message
news:f7a06a7e-b97c-47bd...@m16g2000yqc.googlegroups.com...
They'd better change their Duracells over to Energizer Bunny cells, then.
Dirk Bruere at NeoPax
Latest record is around 190 lm/W
http://en.wikipedia.org/wiki/Luminous_efficacy
--
Dirk
http://www.transcendence.me.uk/ - Transcendence UK
http://www.theconsensus.org/ - A UK political party
http://www.blogtalkradio.com/onetribe - Occult Talk Show
Androcles
"Dirk Bruere at NeoPax" <dirk....@gmail.com> wrote in message
news:7obgcuF...@mid.individual.net...
> Ron Peterson wrote:
>> On Dec 5, 9:19 am, "Androcles" <Headmas...@Hogwarts.physics_q> wrote:
>>
>>> The latest fireflies from Nature now produce more than a million times
>>> the
>>> amount
>>> of light that a compact LED produces for even less electrical power.
>>
>> White LEDs can have an efficiency of 22% currently compared to a
>> maximum possible efficiency for white light of 37%, fireflies are only
>> 96% efficient.
>
> Latest record is around 190 lm/W
> http://en.wikipedia.org/wiki/Luminous_efficacy
>
> --
> Dirk
How many watts does a firefly use, then?
Dirk Bruere at NeoPax
No idea, but it is far higher efficiency than any current LED
Androcles
> Androcles wrote:
>> "Dirk Bruere at NeoPax" <dirk....@gmail.com> wrote in message
>> news:7obgcuF...@mid.individual.net...
>>> Ron Peterson wrote:
>>>> On Dec 5, 9:19 am, "Androcles" <Headmas...@Hogwarts.physics_q> wrote:
>>>>
>>>>> The latest fireflies from Nature now produce more than a million times
>>>>> the
>>>>> amount
>>>>> of light that a compact LED produces for even less electrical power.
>>>> White LEDs can have an efficiency of 22% currently compared to a
>>>> maximum possible efficiency for white light of 37%, fireflies are only
>>>> 96% efficient.
>>> Latest record is around 190 lm/W
>>> http://en.wikipedia.org/wiki/Luminous_efficacy
>>>
>>> --
>>> Dirk
>>
>> How many watts does a firefly use, then?
>
> No idea, but it is far higher efficiency than any current LED
>
idea what "none" is.
Peter Cole
According to this:
http://www.nature.com/nphoton/journal/v2/n1/full/nphoton.2007.251.html
and this:
http://www.bioluminescentbeetles.com/introduction.html
New measurements put quantum efficiency of firefly bioluminescence at 41
+/- 7.4%.
"Initially predicted to be around 88% efficient the firefly
bioluminescent quantum yield has recently been accurately identified to
be 41.0 � 7.4% which is still higher than those found in other forms of
bioluminescence, i.e. aequorin (17%), cypridina (28%) and bacteria (30%)
[4]."
me
> me wrote:
> > It's obvious that the mundane "white" LED bicycle lights do not light
> > up the asphalt roads very well. Incandescents, halogens, and sodium
> > lights do better.
>
> Oh. Last week I had the chance to compare a well respected halogen lamp
> (BuM Lumotec Oval) to a well respected LED lamp (BuM IQ Fly) on the same
> (unlit, asphalt) road at the same time, both running from dynoubs on
> side by side bikes, and the IQ Fly did a damn site better job of
> lighting it up.
>
> So obvious to some, perhaps, but not me.
>
> Pete.
> --
ok,
So it looks like I'll have to to some unbiased testing. It will take
a while. Lifestyle hardships get in the way. Just a homeless bum,
you know.
There are issues involving
1. Spectral distribution from the emitting sources of light
2. Spectral reflectance from whatever the light hits
3. Reflective intensity of the individual colors
4. Spectral perception of the individual
5. Calibration of the reflected colors from a camera device and the
display device
6. Mathematical dealings with superposition issues
I have the 'digital color utility' on my aging mac and an older
digital camcorder that I use for stills. I don't have a high quality
LED lamp which costs too much for me to buy so maybe I'll be able to
borrow one to test. I have an ancient 35mm camera with a light meter
that I will have to calibrate and buy a battery for. I'll have to buy
a few LED's and potentiometers from a parts store. I'll try to mount
them on a dissected cateye opticube. I'll use my cheap digital
voltmeter to get the relation between power and illumination. I have
a diffraction grating that might reveal something. I'll mount it on a
toilet paper roll with a slit on the other end, and attach it to the
camera. I'll use my set of oil crayons for color reference that I
previously used to make a panhandling sign.
I figure I'll eventually shoot around 50 still pix. I might add a set
of fluorescent light pix. I suppose I'll web it up eventually.
errata -
1. many asphalt streets I've seen have varying amounts of small
exposed stones (limestone?) embedded on the surface that will reflect
yellows better than blues. Trees and foliage have a lot of yellow
reflectance.
2. Older people may experience yellowing of the lens in their eyes,
causing less sensitivity to blues. Recently I recommended a 2 front-
light setup for a 60-something biker - one small blue-light flasher,
and a larger halogen with adjustable focus mounted on a flashlight
holder. If you use the halogen only occasionally, the batteries
should last a long time :)
thirty-six
You'll also want a reference grey card (shirt card) and a tape
measure..
Frank Krygowski
Alternately, you could ride your bike and look. That's worked for
many of us.
It's a simple plan, but we like it.
- Frank Krygowski
N8N
> me wrote:
> > It's obvious that the mundane "white" LED bicycle lights do not light
> > up the asphalt roads very well. Incandescents, halogens, and sodium
> > lights do better.
>
> Oh. Last week I had the chance to compare a well respected halogen lamp
> (BuM Lumotec Oval) to a well respected LED lamp (BuM IQ Fly) on the same
> (unlit, asphalt) road at the same time, both running from dynoubs on
> side by side bikes, and the IQ Fly did a damn site better job of
> lighting it up.
>
> So obvious to some, perhaps, but not me.
Odd, I recently replaced a standard Lumotec with an IQ Cyo and the
difference to me was astonishing - in favor of the IQ Cyo.
nate
Chalo
>
> Buy a light. If it's not bright enough for you, buy something else.
> With the time you save from NOT doing the tests you outlined, study
> investments. You'll make much more money than you'll ever spend on
> lights.
Oy! If only it were so!
thirty-six
I've already sorted that. In conditions were road lighting could be
better and I need projection on the road, by current blue tint LED
mixes well with the available yellow sodium. Under better road
lighting then the blueness is more noticeable to other road users.
With no road lighting, the level of illumination is relatively poor
and is best supplemented with an incandescent of normal 2-3W levels.
it would be nice to see specifically what defects are and are not
shown up by the LED without risking riding unlit roads.at speed.
tj Frazir
glow in the dark fluid can take light from outside to inside at the same
time its a heat pump and makes one hell of a glass floor.
Im amazed when glow in the dark waxes that dont mix colors lova lamp
styal deck blew my mind. Its a glass room and has bright colors of low
in th dark fluids that heat and light the lounge.
tj Frazir
The fire fly is 0.01 candle power.
by injecting acid into neon gas.
Then digesting it and recharged with fart gas thats injected with more
stomic acid.
its a gas acid lamp.
glow in the dark is a light charged acid.
neon gas it both a electric gas and a acid gas.
murcury gas is electric ster .
freon is too dim to use.
florecet carbon ster is cheep.
tj Frazir
17 watt 4 x 7 foot 1.7 inch thick.
think they were 1000 bucks each
tj Frazir
froecent or neon between the sheets of glass with a glass beed evry few
inches to hold them apart.
Its a glass sandwich with 1 inch between full of gas to form a light
bulb in the window.
60 watt 4 x 7 foot .
Ron Peterson
> I've already sorted that. In conditions were road lighting could be
> better and I need projection on the road, by current blue tint LED
> mixes well with the available yellow sodium. Under better road
> lighting then the blueness is more noticeable to other road users.
> With no road lighting, the level of illumination is relatively poor
> and is best supplemented with an incandescent of normal 2-3W levels.
> it would be nice to see specifically what defects are and are not
> shown up by the LED without risking riding unlit roads.at speed.
The rods of the eye are most sensitive to blue light.
--
Ron
Tom Keats
thirty-six <thirt...@live.co.uk> writes:
> On 7 Dec, 08:21, Keitht <KeithT> wrote:
>> Androcles wrote:
>> > "thirty-six" <thirty-...@live.co.uk> wrote in message
>> > Are "white" LEDs legally white. �As in, a white lamp must be fitted to
>> > the front of the vehicle and a red lamp must (usually) be fitted to
>> > the rear and operational during times of darkness.
>> > ==========================================
>> > Yes, they are. If you compare older incandescent car headlights
>> > with later halogen lights one will appear to have a yellow tinge
>> > whilst the other appears bluish. Both are legally white.
>> > �http://www.catdiaries.co.uk/images/photography_personal/img_1.jpg
>> > From a legal standpoint you can use a hurricane lamp if you wish,
>> > or even a candle with a glass wind shield. There is no legal requirement
>> > to use an electric light, the law was made before electric lighting
>> > became commonly available.
>> > �http://img1.photographersdirect.com/img/15262/wm/pd1068794.jpg
>> > Legally the lights are required so that you can be seen, not for you to
>> > see by; in Britain a high brightness red rear fog lamp is now a legal
>> > requirement.
>>
>> That was the issue all along - that it's based on power not brightness.
>> It's how you can have incredibly bright car headlights based on halogen
>> and other metals and really shite yellowish bulbs that are still bits of
>> coiled wire - both are perfectly legal as the power consumption is the
>> same.
>> LED's gave us the chance to 'shine', the battery life is a bonus.
>>
> I don't think there is any point in attempting to compete with car
> headlights.
There seems to be a mindset that that is indeed what
bike riders need to do, either in terms of o/p wattage
or brightness. In city traffic, blinking lights + speed
difference + positioning on the street does the trick
nicely -- as long as the batteries don't fade.
On lightly-driven country highways at night, just about
any kind of light sticks out like a sore thumb.
> If we can obtain similar brightness and size to a 24W
> incandescent (not legal) reversing lamp then we have all the
> visibility requirements we need. Experience shows this is way in
> excess of what we need to illuminate the road effevtively. I have a
> flood type car headlamp reflector of around 3" and would like to see
> this with an LED driver fitted if possible.
It's very nice to be able to cast a luminous spot on the
city streets at night when approaching intersections in order
to announce one's approach to any possible cross traffic;
epecially at blind intersections, which should be dealt
with gingerly anyways. 'Cuz chances are, any cross-traffic
drivers there won't be alert to the approach of car
headlights, let alone bike lights. So we have to be
alert for them.
I guess just having lights on is no excuse for having
one's guard down.
cheers,
Tom
--
Nothing is safe from me.
I'm really at:
tkeats curlicue vcn dot bc dot ca
Just zis Guy, you know?
And the people who actually know about lighting are audax riders, who
ride in all kinds of lighting conditions right down to pitch black and
in all kinds of weathers.
I'd also suggest that anyone who judges LED lights without having
tried the most recent offerings from B&M and others, is probably not
going to be in possession of all the facts. They have improved
dramatically in recent times. A D-Lumotec might justly be
characterised as thirty-six described, but the IQ Cyo definitely
can't.
LEDs have definitely moved from the being-seen into the seeing-by
category.
Androcles
"Tom Keats" <tkeat...@hotmail.com> wrote in message
news:jpevfh...@news.eternal-september.org...
The weight won't affect your speed, just your acceleration,
and when you get tired pedalling you can run a motor from
it. Electrically propelled bicycles have been around for a while
now.
Anyway, bikes are faster than cars in city traffic which is why
couriers use them.
G=EMC^2 Glazier
Tang TheirMafia toast will go like this. Why live a life of hell on
earth when God will be waiting in heaven for you with food and drink up.
Muslins know sex is better than food so their God has 72 virgins waiting
with legs spread. Reality is the Godfather hates poor people. However he
does have a warm spot and give them a dose of opium to take away the
pain of Tang. That is the reason the Godfather has people dying to save
his poppies in Afghanistan O ya it fits Especially when you live in
Florida with the "good old boys" Bert
Helmut Wabnig
LEDs containing Arsen (galliumarsenide) will cause the
NHS "Napoleon St. Helena Syndrome" by As-poisoning.
Symptoms are: senility.
Side note:
Napoleon's green As-contaminated wallpapers were made
by a German manufacturer. Justice at last.
(Napoleon died of stomach cancer).
w.
Clive George
news:b1482fc0-b516-42fa...@b15g2000yqd.googlegroups.com...
I think you'll find you're agreeing with Pete :-)
Tim McNamara
<126f2384-ca8d-4230...@f18g2000prf.googlegroups.com>,
me <dhm_at_be...@yahoo.com> wrote:
> On Dec 7, 1:30�am, Peter Clinch <p.j.cli...@dundee.ac.uk> wrote:
>
> > me wrote:
> > > It's obvious that the mundane "white" LED bicycle lights do not
> > > light up the asphalt roads very well. �Incandescents, halogens,
> > > and sodium lights do better.
> >
> > Oh. �Last week I had the chance to compare a well respected halogen
> > lamp (BuM Lumotec Oval) to a well respected LED lamp (BuM IQ Fly)
> > on the same (unlit, asphalt) road at the same time, both running
> > from dynoubs on side by side bikes, and the IQ Fly did a damn site
> > better job of lighting it up.
> >
> > So obvious to some, perhaps, but not me.
> >
> > Pete. --
>
> ok,
>
> So it looks like I'll have to to some unbiased testing. It will take
> a while. <snip>
>
> I figure I'll eventually shoot around 50 still pix. I might add a
> set of fluorescent light pix. I suppose I'll web it up eventually.
Most of this has been done already. Why try to reinvent the wheel?
Comparing LEDs with halogens for bike lights, the current LEDS have
already surpassed halogens and will continue to improve. Halogens are a
mature technology and unlikely to improve significantly in this
application.
The photos are on the Web already. Google around. Start with Peter
White Cycles; Peter has posted quite a few comparison photos.