LED's for running lights?

Meindert Sprang wrote:
 > "lupi" <snuffles.DeleteThis@snottering.com> wrote in message
 > news:2fkeq05ij6udipb57bu8mp3mqki43skcsu@4ax.com...
 >
  >>Also, I want to make an anchor light with 6 of the 60 degree lamps
  >>flashing so fast they look like they are all on- kind of like the
  >>moving pictures principle. A 555 timer chip, a capacitor, a current
  >>limiting resistor? In theory this would still only drawn the current
  >>of one lamp. Is any of this practical? Thanks again.
 >
 >
 > An anchor light is not supposed (or even allowed to) flash.....
 >
 > Meindert
 >
 >
I believe he wants to strobe them faster than the eye can percieve.
something like 50 hz would do it.


--
""War is an ugly thing, but not the ugliest of things. The decayed and
degraded state of moral and patriotic feeling which thinks that nothing
is worth war is much worse."
    John Stewart Mill


I strongly urge everyone reading this to check out <a style='text-decoration: underline;' href="http://WWW.anysoldier.us," target="_blank">WWW.anysoldier.us,</a>
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 >> Stay informed about: LED's for running lights? 

I think he wants to flash them beyond the threshold of perception. What's
that...about 20 hertz? But isn't there something off the shelf that would be
simpler than breadboarding transistors?
At the rate LEDs are taking over lighting the world, somebody in Taiwan may
have solved this problem already.
Good luck,
Boat_dreams.
 >> Stay informed about: LED's for running lights? 

You can buy LED lights for a reasonable price down at the local truck stop,
but how do you mount these puppies? Anybody know? It's just got the lamp
itself, no mounting hardware ...the guy at the counter is clueless. Looks
like maybe they are designed to fit in a rubber channel or something?
Anybody?

Brian D

PS: These are cheaper than buying the LED tail lights designed for boat
trailers, so it could mean a cheap upgrade if I can figure out the right way
to mount them....
 >> Stay informed about: LED's for running lights? 

"dazed and confuzed" <dedmann.RemoveThis@netnitco.net> wrote in message
news:w7idndVB7t97YTrcRVn-og@netnitco.net...
 > I believe he wants to strobe them faster than the eye can percieve.
 > something like 50 hz would do it.

Ah, now I understand. But this has no benefits. A LED that is continuously
on at, say 20mA, will appear to have the same brightness as when strobed
with a 20% duty-cycle (1/5 of the time) at 100mA (5 times the current).

Meindert<!-- ~MESSAGE_AFTER~ -->
 >> Stay informed about: LED's for running lights? 

On Sat, 27 Nov 2004 08:03:59 +0100, "Meindert Sprang"
<mhsprang.RemoveThis@NOcustomSPAMware.nl> vaguely proposed a theory
.......and in reply I say!:

remove ns from my header address to reply via email

 >"dazed and confuzed" <dedmann.RemoveThis@netnitco.net> wrote in message
 >news:w7idndVB7t97YTrcRVn-og@netnitco.net...
  >> I believe he wants to strobe them faster than the eye can percieve.
  >> something like 50 hz would do it.
 >
 >Ah, now I understand. But this has no benefits. A LED that is continuously
 >on at, say 20mA, will appear to have the same brightness as when strobed
 >with a 20% duty-cycle (1/5 of the time) at 100mA (5 times the current).
 >
 >Meindert
 >


Actually not quite. If you talk energy consumption then you are right.
But you can viciously overdrivve LEDs to get far more brightness out
of then than they normally can give.

see:
<a style='text-decoration: underline;' href="http://www.stockeryale.com/i/leds/lit/app001.htm" target="_blank">http://www.stockeryale.com/i/leds/lit/app001.htm</a>

There is also argument that your eye and brain think that the led is
still alight and this can fool you into seeing a brighter LED. I would
reckon this would work best for LEDs being looked _at_, rather than
thiose used as a source of illumination.<!-- ~MESSAGE_AFTER~ -->
 >> Stay informed about: LED's for running lights? 

Actually, they do this in bicycle safety lights all of the time- even
when they're slowly flashing, they are also flickering at high speed.
There is a net savings in power consumption at an equivallent
brightness, but I don't have the figures handy. A 555, one capacitor
and one resistor will set you back about 75 cents, and the circut is
easy enough for you to have your cat do it.



"Meindert Sprang" <mhsprang.DeleteThis@NOcustomSPAMware.nl> wrote in message news:<10qg9l8mbrt4ge1.DeleteThis@corp.supernews.com>...
 > "dazed and confuzed" <dedmann.DeleteThis@netnitco.net> wrote in message
 > news:w7idndVB7t97YTrcRVn-og@netnitco.net...
  > > I believe he wants to strobe them faster than the eye can percieve.
  > > something like 50 hz would do it.
 >
 > Ah, now I understand. But this has no benefits. A LED that is continuously
 > on at, say 20mA, will appear to have the same brightness as when strobed
 > with a 20% duty-cycle (1/5 of the time) at 100mA (5 times the current).
 >
 > Meindert<!-- ~MESSAGE_AFTER~ -->
 >> Stay informed about: LED's for running lights? 

"Old Nick" <nsnsafemail RemoveThis @dodo.com.au> wrote in message
news:6mogq05gufi9b9lj5ci19ej9t22khil6br@4ax.com...
 > Actually not quite. If you talk energy consumption then you are right.
 > But you can viciously overdrivve LEDs to get far more brightness out
 > of then than they normally can give.
 >
 > see:
<font color=purple> > <a style='text-decoration: underline;' href="http://www.stockeryale.com/i/leds/lit/app001.htm</font" target="_blank">http://www.stockeryale.com/i/leds/lit/app001.htm</font</a>>

I know, I have used that principle to drive IR leds to illuminate a scenery
for the time of one frame of a video camera.

 > There is also argument that your eye and brain think that the led is
 > still alight and this can fool you into seeing a brighter LED. I would
 > reckon this would work best for LEDs being looked _at_, rather than
 > thiose used as a source of illumination.

Mmm.... I'd thought that the eye/brain combination would average it, but on
the other hand, the mind can do strange thinks. I'll might try it some day
by comparing two LEDs next to eachother, one continuously driven and the
other with a duty cycle.

Meindert<!-- ~MESSAGE_AFTER~ -->
 >> Stay informed about: LED's for running lights? 

Thank you very much for the anysoldier link. I am a contractor who came back
from Iraq on a stretcher with 3 pints of someone else's blood in me. I feel
a very close personal bond to our sons and daughters over there.
To make war for personal gain or to impose personal beliefs upon others is,
in itself, a form of terrorism. To make war for personal financial and
political gain is reprehensible and will be tried by the highest court: God.
"To announce that there must be no criticism of the president, or that we
are to stand by the president, right or wrong, is not only unpatriotic and
servile, but is morally treasonable to the American public."
- President Theodore Roosevelt

 > ""War is an ugly thing, but not the ugliest of things. The decayed and
 > degraded state of moral and patriotic feeling which thinks that nothing is
 > worth war is much worse."
 > John Stewart Mill
 >
 >
 > I strongly urge everyone reading this to check out <a style='text-decoration: underline;' href="http://WWW.anysoldier.us," target="_blank">WWW.anysoldier.us,</a> and
 > support our troops with a letter, a package or a donation.
 ><!-- ~MESSAGE_AFTER~ -->
 >> Stay informed about: LED's for running lights? 

You need to do it as a blind study. Your preknowledge of which is driven
how may color your perception in something as subtle as that.

--
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"Meindert Sprang" <mhsprang RemoveThis @NOcustomSPAMware.nl> wrote in message
news:10qh6po4ngon2b1@corp.supernews.com...
 > "Old Nick" <nsnsafemail RemoveThis @dodo.com.au> wrote in message
 > news:6mogq05gufi9b9lj5ci19ej9t22khil6br@4ax.com...
  > > Actually not quite. If you talk energy consumption then you are right.
  > > But you can viciously overdrivve LEDs to get far more brightness out
  > > of then than they normally can give.
  > >
  > > see:
<font color=green>  > > <a style='text-decoration: underline;' href="http://www.stockeryale.com/i/leds/lit/app001.htm</font" target="_blank">http://www.stockeryale.com/i/leds/lit/app001.htm</font</a>>
 >
 > I know, I have used that principle to drive IR leds to illuminate a
scenery
 > for the time of one frame of a video camera.
 >
  > > There is also argument that your eye and brain think that the led is
  > > still alight and this can fool you into seeing a brighter LED. I would
  > > reckon this would work best for LEDs being looked _at_, rather than
  > > thiose used as a source of illumination.
 >
 > Mmm.... I'd thought that the eye/brain combination would average it, but
on
 > the other hand, the mind can do strange thinks. I'll might try it some day
 > by comparing two LEDs next to eachother, one continuously driven and the
 > other with a duty cycle.
 >
 > Meindert
 >
 ><!-- ~MESSAGE_AFTER~ -->
 >> Stay informed about: LED's for running lights? 

On Fri, 26 Nov 2004 17:07:30 +0000, lupi wrote:

 > Any info on this? The 12v single water clear led's are $1.67 and put
 > out 11000 or 3300 mcd, whatever that is, some measure of how bright
 > they are. The viewing angle is 30 or 60 degrees. The attraction is
 > that current draw is almost nothing. I measured .023 amps for a single
 > lamp.
 > Also, I want to make an anchor light with 6 of the 60 degree lamps
 > flashing so fast they look like they are all on- kind of like the
 > moving pictures principle. A 555 timer chip, a capacitor, a current
 > limiting resistor? In theory this would still only drawn the current
 > of one lamp. Is any of this practical? Thanks again.

Well, if you want to multiplex 6 lamps, then you will need to have a
maximum duty cycle of 100/6 = ~18 % for each lamp.

While you can certainly flash LED's without losing any apparent
brightness (I think I've read that rapidly flashing LED's can subjectively
appear brighter to observers) you can't arbitrarily go down to low duty
cycles, and I think 18% is too low.

Still, maybe you should just build the circuit with one LED and see what
it looks like at an 18% duty cycle.

If you need help with the circuit, try one of these two newsgroups:

sci.electronics.basics
sci.electronics.design

--Mac<!-- ~MESSAGE_AFTER~ -->
 >> Stay informed about: LED's for running lights? 

On Sat, 27 Nov 2004 16:21:18 +0100, "Meindert Sprang"
<mhsprang.TakeThisOut@NOcustomSPAMware.nl> vaguely proposed a theory
.......and in reply I say!:

remove ns from my header address to reply via email

 >"Old Nick" <nsnsafemail.TakeThisOut@dodo.com.au> wrote in message
 >news:6mogq05gufi9b9lj5ci19ej9t22khil6br@4ax.com...
  >> Actually not quite. If you talk energy consumption then you are right.
  >> But you can viciously overdrivve LEDs to get far more brightness out
  >> of then than they normally can give.
  >>
  >> see:
<font color=green>  >> <a style='text-decoration: underline;' href="http://www.stockeryale.com/i/leds/lit/app001.htm</font" target="_blank">http://www.stockeryale.com/i/leds/lit/app001.htm</font</a>>
 >
 >I know, I have used that principle to drive IR leds to illuminate a scenery
 >for the time of one frame of a video camera.

OK. Sorry. Then I misunderstood your argument, unless you were talking
about actual efficiency. You seemed to say that strobing had no gain.

 >
  >> There is also argument that your eye and brain think that the led is
  >> still alight and this can fool you into seeing a brighter LED. I would
  >> reckon this would work best for LEDs being looked _at_, rather than
  >> thiose used as a source of illumination.
 >
 >Mmm.... I'd thought that the eye/brain combination would average it, but on
 >the other hand, the mind can do strange thinks. I'll might try it some day
 >by comparing two LEDs next to eachother, one continuously driven and the
 >other with a duty cycle.

I carefully said there was "some argument" about this! <G> ABob says,
you need to test with extreme care.<!-- ~MESSAGE_AFTER~ -->
 >> Stay informed about: LED's for running lights? 

Thanks everyone. I should have mentioned that I have a 6 sided glass
jar for my anchor light housing. I hope heat won't be a problem. As
the LED's have a 60degree viewing angle I figured it would be visible
360degrees. (6x60=360- my best math). The flashing idea was just to
save battery power. I did find an anchor light at BoatUS for $42usd
that had it's own solar cel and batteries so maybe I'll just run that
up to a spreader. I just wondered if any other sailors had rigged
their running lights for LED as battery power can be a problem. The
11000 mcd is blinding when viewed directly but in a lense might not be
to reg. Thanks again.

On Sat, 27 Nov 2004 19:36:56 GMT, Mac <foo DeleteThis @bar.net> wrote:

 >On Fri, 26 Nov 2004 17:07:30 +0000, lupi wrote:
 >
  >> Any info on this? The 12v single water clear led's are $1.67 and put
  >> out 11000 or 3300 mcd, whatever that is, some measure of how bright
  >> they are. The viewing angle is 30 or 60 degrees. The attraction is
  >> that current draw is almost nothing. I measured .023 amps for a single
  >> lamp.
  >> Also, I want to make an anchor light with 6 of the 60 degree lamps
  >> flashing so fast they look like they are all on- kind of like the
  >> moving pictures principle. A 555 timer chip, a capacitor, a current
  >> limiting resistor? In theory this would still only drawn the current
  >> of one lamp. Is any of this practical? Thanks again.
 >
 >Well, if you want to multiplex 6 lamps, then you will need to have a
 >maximum duty cycle of 100/6 = ~18 % for each lamp.
 >
 >While you can certainly flash LED's without losing any apparent
 >brightness (I think I've read that rapidly flashing LED's can subjectively
 >appear brighter to observers) you can't arbitrarily go down to low duty
 >cycles, and I think 18% is too low.
 >
 >Still, maybe you should just build the circuit with one LED and see what
 >it looks like at an 18% duty cycle.
 >
 >If you need help with the circuit, try one of these two newsgroups:
 >
 >sci.electronics.basics
 >sci.electronics.design
 >
 >--Mac<!-- ~MESSAGE_AFTER~ -->
 >> Stay informed about: LED's for running lights? 

On Sat, 27 Nov 2004 10:29:14 -0700, "Bob La Londe"
<usenet DeleteThis @diycomponents.com> vaguely proposed a theory
.......and in reply I say!:

remove ns from my header address to reply via email

>You need to do it as a blind study.

Now _that_ would be fruitless! <G>

>Your preknowledge of which is driven
>how may color your perception in something as subtle as that.

I agree however.
 >> Stay informed about: LED's for running lights?