Where to find info

[Flash]

I would like to find info on how to wire large groups of LEDs. Just an art
project, but I am curious.

I wish to assemble a large group of LEDs in a certain pattern and wish to
know how to control them for on/off without using hundreds of miles of wire.

Any pointers would certainly be welcome.

Thanks,

Flash

 

[[email protected]]

I would like to find info on how to wire large groups of LEDs.  Just anart
project, but I am curious.

I wish to assemble a large group of LEDs in a certain pattern and wish to
know how to control them for on/off without using hundreds of miles of wire.

Any pointers would certainly be welcome.

Thanks,

Flash

--
Today, we hear shameful fear mongering from an administration that can no
longer hide its lust to open the floodgates filled with our money, so they
can buy off reliable Democrat constituencies.
....Mark Davis

Do you mean you wish to be able to turn each one on and off
individually without running a wire from each led all the way back to
your "control"? There are ways to do that but it would help to know
about how many you are talking about and the size of your display.

 

[Charles]

I would like to find info on how to wire large groups of LEDs. Just an art
project, but I am curious.

I wish to assemble a large group of LEDs in a certain pattern and wish to
know how to control them for on/off without using hundreds of miles of
wire.

Any pointers would certainly be welcome.

You can put them in series and you can arrange them in an X-Y matrix. Given
the current array of cheap microcontrollers, you can do really neat stuff!

 

[Flash]

You can put them in series and you can arrange them in an X-Y matrix.
Given the current array of cheap microcontrollers, you can do really neat
stuff!

and jamesg wrote: >"Do you mean you wish to be able to turn each one on and
off

individually without running a wire from each led all the way back to
your "control"? There are ways to do that but it would help to know
about how many you are talking about and the size of your display."

and John Fields said: >"Give us some more information and I'm sure at
least a few of us will be

happy to help you."

So, thanks, you have already helped me narrow my questions.

I want a farily large group, maybe 600 or so, and I wish to be able to turn
them on/off, individually, I know it is possible to do this with 2 wires to
each LED, but I guess I would like to do this without much background, like
board or such. Kind of an open-space effect, with LED's in it.But still,
with the ability to turn them on and off at will, to a certain pattern.

Thanks,

And now for the second round, now that your interest has helped to distill
my thought into words.

Flash

 

[Charles]

and jamesg wrote: >"Do you mean you wish to be able to turn each one on and
off

and John Fields said: >"Give us some more information and I'm sure at
least a few of us will be



So, thanks, you have already helped me narrow my questions.

I want a farily large group, maybe 600 or so, and I wish to be able to turn
them on/off, individually, I know it is possible to do this with 2 wires to
each LED, but I guess I would like to do this without much background, like
board or such. Kind of an open-space effect, with LED's in it.But still,
with the ability to turn them on and off at will, to a certain pattern.

Thanks,

And now for the second round, now that your interest has helped to distill
my thought into words.

Flash

A row and column matrix maybe, strobing which ones you want on at the
time. High enough strobe rate should look like they are on
continuously.

 

[[email protected]]

and jamesg wrote:  >"Do you mean you wish to be able to turn each one on and

off


and John Fields said:   >"Give us some more information and I'm sure at
least a few of us will be


So, thanks, you have already helped me narrow my questions.

I want a farily large group, maybe 600 or so, and I wish to be able to turn
them on/off, individually, I know it is possible to do this with 2 wires to
each LED, but I guess I would like to do this without much background, like
board or such.  Kind of an open-space effect, with LED's in it.But still,
with the ability to turn them on and off at will, to a certain pattern.

Thanks,

And now for the second round, now that your interest has helped to distill
my thought into words.

Flash- Hide quoted text -

- Show quoted text -

Perhaps you should also look at very thin wire. Leds don't draw much
so it is possible to run them with some pretty small enameled wire.

If what you hold the leds with is metal then that can serve as one of
your wires. One solution is to run a wire back to a central board
from each led. The second wire, the "common", can dasiy chain from
led to led.

Or you have to build an addressing mechanism with each led that lets
you turn it on and off via a digital signal sent over a common power
lead. That solution would let you daisy chain leds along a single
pair of wires but would require a small circuit board with each one.
There may be single chip solutions to this. Times 600 could be a
little pricy as compared to running a wire from each led all the way
back to a central control board.

Either way you will need to interface this to a pc to control your
collection of leds. Theer are many already built solutions to help
connect your controls to a pc..

 

[Jerry Avins]

---
If you used something like this:

http://www.allegromicro.com/en/Products/Part_Numbers/6276/6276.pdf

You could use one chip to control (on-off) 16 LEDs, or 38 chips to
control 600.

The advantage is that you could have the chips interspersed in the array
with 16 very thin nearly invisible wires going to the LEDs it controlled
in its part of the array. Also required would be a wire for the
positive supply, a wire for ground, and a wire for serial data, data
clock, and latch enable. Four of those wires would be connected to all
of the chips and would be run like a bus to them all. Serial data would
be daisy-chained between the chips, and the positive supply would also
have to go to all the LED anodes, and one wire could be run in order to
do that.

Another advantage is that the display would be static. That is, no
multiplexing would be involved and you could update the display as
quickly or as slowly as you wanted in order to get the effect you
wanted.

Low duty cycle provides more brightness for the same average current. To
the extent that the /on/ voltage is independent of current, the same
average current yields the same average power.

Jerry

 

[Jerry Avins]

---
Under certain conditions that's true, but generally it isn't.

For instance, an LED being fed 10mA continuously will appear to be as
bright as an LED pulsed with a 10% duty cycle 100mA pulse.

That is, assuming the LED produces 10 times the illumination for 10
times the current.

The point is, it doesn't. efficiency is often greater at higher current.
This was certainly true with red LEDs from Hewlett-Packard.

---


And, hence, the same illumination, so low duty cycle _doesn't_ provide
more brightness for the same average current,

Actually, no. With quantum efficiency rising, more light out means less
heat. The I^2*R losses go up, though, so you don't come out ahead.

Jerry

 

[Jerry Avins]

Jerry Avins wrote:

...

The point is, it doesn't. efficiency is often greater at higher current.
This was certainly true with red LEDs from Hewlett-Packard.

Actually, no. With quantum efficiency rising, more light out means less
heat. The I^2*R losses go up, though, so you don't come out ahead.

I omitted a significant effect: the eye's nonlinear perception of
brightness. For inputs faster than the persistence of vision, it acts
partly like a peak detector.

Jerry

 

[Flash]

---
If you used something like this:

http://www.allegromicro.com/en/Products/Part_Numbers/6276/6276.pdf

You could use one chip to control (on-off) 16 LEDs, or 38 chips to
control 600.

The advantage is that you could have the chips interspersed in the array
with 16 very thin nearly invisible wires going to the LEDs it controlled
in its part of the array. Also required would be a wire for the
positive supply, a wire for ground, and a wire for serial data, data
clock, and latch enable. Four of those wires would be connected to all
of the chips and would be run like a bus to them all. Serial data would
be daisy-chained between the chips, and the positive supply would also
have to go to all the LED anodes, and one wire could be run in order to
do that.

Another advantage is that the display would be static. That is, no
multiplexing would be involved and you could update the display as
quickly or as slowly as you wanted in order to get the effect you
wanted.

JF

Boy, you guys just keep expanding the horizons, here. I came to you with
this half-formed idea ( Confucius say: "Never begin vast project with
half-vast idea") and you have really helped me see that I am drawn up
agianst a concept that has more than one elegant solution.

I approach this venture as an artist, though I do have a bit of electronics
training, a half a century ago, courtesy of the USAF. It is an art object
which I intend to fabricate, but the artist needs a thorough understanding
of the chosen media. Therefore, I have a lot of reading and learning to do
in the immediate future. In just a couple of days, you have given me a
number of terms and processes that I need to know. I hesitate to beg a
"reading list", but if you have a favorite on planning circuits such as you
have mentioned, I'd certainly appreciate a tip or two.

I still contend that usenet is a great community, populated by exceptional
individuals, the flame-wars and invectivefound on other NG's
notwithstanding. Proof exists, right here.

Thanks, folks. When the project comes up to daylight, you will be the first
invited to critique.

Flash

 

[[email protected]]

Boy, you guys just keep expanding the horizons, here.  I came to you with
this half-formed idea ( Confucius say: "Never begin vast project with
half-vast idea") and you have really helped me see that I am drawn up
agianst a concept that has more than one elegant solution.

I approach this venture as an artist, though I do have a bit of electronics
training, a half a century ago, courtesy of the USAF. It is an art object
which I intend to fabricate, but the artist needs a thorough understanding
of the chosen media. Therefore, I have a lot of reading and learning to do
in the immediate future. In just a couple of days, you have given me a
number of terms and processes that I need to know.  I hesitate to beg a
"reading list", but if you have a favorite on planning circuits such as you
have mentioned, I'd certainly appreciate a tip or two.

I still contend that usenet is a great community, populated by exceptional
individuals, the flame-wars and invectivefound on other NG's
notwithstanding. Proof exists, right here.

Thanks, folks.  When the project comes up to daylight, you will be the first
invited to critique.

Flash- Hide quoted text -

- Show quoted text -

I think you've about exhausted the possibilties already. Unless you
provide more specifics about the physical construction you're going to
have to make the choice between the various options offered yourself.
There is a lot of material that will come up using some pretty simple
google searches but which avenue you should take is hard to say given
the limited info you have provided.

 

[[email protected]]

Boy, you guys just keep expanding the horizons, here.  I came to you with
this half-formed idea ( Confucius say: "Never begin vast project with
half-vast idea") and you have really helped me see that I am drawn up
agianst a concept that has more than one elegant solution.

I approach this venture as an artist, though I do have a bit of electronics
training, a half a century ago, courtesy of the USAF. It is an art object
which I intend to fabricate, but the artist needs a thorough understanding
of the chosen media. Therefore, I have a lot of reading and learning to do
in the immediate future. In just a couple of days, you have given me a
number of terms and processes that I need to know.  I hesitate to beg a
"reading list", but if you have a favorite on planning circuits such as you
have mentioned, I'd certainly appreciate a tip or two.

I still contend that usenet is a great community, populated by exceptional
individuals, the flame-wars and invectivefound on other NG's
notwithstanding. Proof exists, right here.

Thanks, folks.  When the project comes up to daylight, you will be the first
invited to critique.

Flash- Hide quoted text -

- Show quoted text -

You might look into video systems. Many LARGE screens are LED arrays.
(6" spacing on 30' x 50' of fabric)

The drivers and software might be expensive but the engineering is
already done.

--RickR

 

[Flash]

Boy, you guys just keep expanding the horizons, here. I came to you with
this half-formed idea ( Confucius say: "Never begin vast project with
half-vast idea") and you have really helped me see that I am drawn up
agianst a concept that has more than one elegant solution.

I approach this venture as an artist, though I do have a bit of
electronics
training, a half a century ago, courtesy of the USAF. It is an art object
which I intend to fabricate, but the artist needs a thorough understanding
of the chosen media. Therefore, I have a lot of reading and learning to do
in the immediate future. In just a couple of days, you have given me a
number of terms and processes that I need to know. I hesitate to beg a
"reading list", but if you have a favorite on planning circuits such as
you
have mentioned, I'd certainly appreciate a tip or two.

I still contend that usenet is a great community, populated by exceptional
individuals, the flame-wars and invectivefound on other NG's
notwithstanding. Proof exists, right here.

Thanks, folks. When the project comes up to daylight, you will be the
first
invited to critique.

Flash- Hide quoted text -

- Show quoted text -

I think you've about exhausted the possibilties already. Unless you
provide more specifics about the physical construction you're going to
have to make the choice between the various options offered yourself.
There is a lot of material that will come up using some pretty simple
google searches but which avenue you should take is hard to say given
the limited info you have provided.




That's just the thing: I am still working, myself, with limited
information. What I eventually will do will/must depend a lot on what I can
do with regard to how many LEDs are in a given volume of space, and how
unobtrusive I can make the physical support structure, and how I can conceal
the wiring (and THAT is a function of how the wiring is done.) I want the
LEDs to be unobstructed by the support structure.

I have visions of a cylindrical volume of space, with LEDs (colors and
white) in an X-Y-Z arrangement in that space, the image being created by the
lighting of the LEDs. I have experience with sign lighting, sequencing,
flashing, running lights, and had hoped to infuse some of those illusions of
motion into the LED pattern.

Your input has given me cause to re-think controllers, for in the
electrical-sign method, each light, LED in this case, must be individually
wired, or I could have a four-wire or six-wire raceway type of thing. But
each one still would be individually wired. The wiring and the support
structure will have a large presence (therefore visually undesirable) in the
open space.

Perhaps aluminum tube support, also as common condudctor, with the control
wiring inside the tube. But then how much wire can I cram into what size
tube, and how much weight will it support becomes the next question. I'll
probably design it for small and light, first. And maybe 800 LEDs is an
optimistic figure.

Time for me to do some real research, not just artistic considerations. But
you have helped clarify the thinking.

Thanks, all.

Flash

 

[Charles]

I think you've about exhausted the possibilties already. Unless you
provide more specifics about the physical construction you're going to
have to make the choice between the various options offered yourself.
There is a lot of material that will come up using some pretty simple
google searches but which avenue you should take is hard to say given
the limited info you have provided.




That's just the thing: I am still working, myself, with limited
information. What I eventually will do will/must depend a lot on what I can
do with regard to how many LEDs are in a given volume of space, and how
unobtrusive I can make the physical support structure, and how I can conceal
the wiring (and THAT is a function of how the wiring is done.) I want the
LEDs to be unobstructed by the support structure.

I have visions of a cylindrical volume of space, with LEDs (colors and
white) in an X-Y-Z arrangement in that space, the image being created by the
lighting of the LEDs. I have experience with sign lighting, sequencing,
flashing, running lights, and had hoped to infuse some of those illusions of
motion into the LED pattern.

Your input has given me cause to re-think controllers, for in the
electrical-sign method, each light, LED in this case, must be individually
wired, or I could have a four-wire or six-wire raceway type of thing. But
each one still would be individually wired. The wiring and the support
structure will have a large presence (therefore visually undesirable) in the
open space.

Perhaps aluminum tube support, also as common condudctor, with the control
wiring inside the tube. But then how much wire can I cram into what size
tube, and how much weight will it support becomes the next question. I'll
probably design it for small and light, first. And maybe 800 LEDs is an
optimistic figure.

Time for me to do some real research, not just artistic considerations. But
you have helped clarify the thinking.

Thanks, all.

Flash

Low current for each wire, look into wire wrap wire, #32 if I recall
correctly. You can get a lot into a small space.

 

[Adam Aglionby]

I think you've about exhausted the possibilties already.  Unless you
provide more specifics about the physical construction you're going to
have to make the choice between the various options offered yourself.
There is a lot of material that will come up using some pretty simple
google searches but which avenue you should take is hard to say given
the limited info you have provided.

That's just the thing:  I am still working, myself, with limited
information. What I eventually will do will/must depend a lot on what I can
do with regard to how many LEDs are in a given volume of space, and how
unobtrusive I can make the physical support structure, and how I can conceal
the wiring (and THAT is a function of how the wiring is done.)  I want the
LEDs to be unobstructed by the support  structure.

I have visions of a cylindrical volume of space, with LEDs (colors and
white) in an X-Y-Z arrangement in that space, the image being created by the
lighting of the LEDs.   I have experience with sign lighting, sequencing,
flashing, running lights, and had hoped to infuse some of those illusionsof
motion into the LED pattern.

Your input has given me cause to re-think controllers, for in the
electrical-sign method, each light, LED in this case, must be individually
wired, or I could have a four-wire or six-wire raceway type of thing.  But
each one still would be individually  wired.  The wiring and the support
structure will have a large presence (therefore visually undesirable) in the
open space.

Perhaps aluminum tube support, also as common condudctor, with the control
wiring inside the tube. But then how much wire can I cram into what size
tube, and how much weight will it support becomes the next question.  I'll
probably design it for small and light, first. And maybe 800 LEDs is an
optimistic figure.

Time for me to do some real research, not just artistic considerations. But
you have helped clarify the thinking.

Thanks, all.

Flash

Have alook at G-Lec one of the original innovators in transluscent LED
screens

http://www.g-lec.com

and Element Labs Stealth

http://www.elementlabs.com/STEALTH.html

Both of them are around same cost as as a manned moon landing..... ;-)

Adam