LED's for running lights?
 

"lupi" wrote in message
...
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 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.

Meindert Sprang wrote:
"lupi" wrote in message
...

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.


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degraded state of moral and patriotic feeling which thinks that nothing
is worth war is much worse."
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I strongly urge everyone reading this to check out WWW.anysoldier.us,
and support our troops with a letter, a package or a donation.

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....

"dazed and confuzed" wrote in message
...
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

On Sat, 27 Nov 2004 08:03:59 +0100, "Meindert Sprang"
vaguely proposed a theory
.......and in reply I say!:

remove ns from my header address to reply via email

"dazed and confuzed" wrote in message
...
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:
http://www.stockeryale.com/i/leds/lit/app001.htm

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.

"Old Nick" wrote in message
...
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:
http://www.stockeryale.com/i/leds/lit/app001.htm

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

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" wrote in message ...
"dazed and confuzed" wrote in message
...
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

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" wrote in message
...
"Old Nick" wrote in message
...
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:
http://www.stockeryale.com/i/leds/lit/app001.htm

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

On Sat, 27 Nov 2004 10:29:14 -0700, "Bob La Londe"
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.