Controlling 400+leds.

Im a bit new to the arduino, and will be embarking on a huge project within the next few months, basically what i wanted to know was the following:

(all leds are RGB btw)

1.Best way to control 400+ leds individually, Without having any flickering. (they wont be in one long chain) 2. How to keep the power up to par for them, (Ive been looking around the fourms and have seen some things about how for 100leds you would need a 5v 2a power supply or something, Im wondering if theres a more direct in-line way of doing this, such as a amp does to subwoofers.

any advice/questions/comments are appreciated :D

Search the board for "multiplex" and start reading. You will need an external power supply that can power the LEDs at their rated specifications.

XMOS uses a 16x32 RGB LED panel with Macroblock LED driver chips in their reference design:

https://www.xmos.com/products/development-kits/led-reference-design-kit

http://www.mblock.com.tw/

A couple of things to keep in mind:

"RGB LED" is a bit of a misnomer: it's really an "LED module", i.e., 3 separate diodes in one package. If you're going to have 400 of them, you'll actually be controlling 1200 LEDs.

It matters a great deal whether you plan to do simple "on/off" control, or to change the color to something other than the basic R, G, and B by varying the intensity of the different LEDs in each package. The former can be done with simpler and cheaper circuits than the latter.

Another thing that can make a big difference is the physical layout: some approaches that work well when all the LEDs are clustered close together don't work (well) if you're decorating a Christmas tree or the wall of a house.

Thanks all for the comments, Im trying to avoid multiplexing as to not make this project anymore complicated than it needs to be.

@Ran Talbott Ill be using PWM to control the leds, not just a simple on or off.

the application for this would be a car, so im trying to figure out if i can just have the output fron the arduino, have those cables go into a amp, then have the output on the LEDs be there true max.

So for some applications, like the tail lights, ill have them in clusters, but then for things like the interior lighting ill have them all over the place.

Will all the LEDs be the same color? Or are you planning to have more than one color showing at the same time?

If the former, you could just use transistors like an "amp" to power the LEDs from the Arduino's PWM.

But be careful: PWMing that much power through long wires could cause noticeable RF interference. You'll want to get some advice from an EE about how to avoid that: wouldn't want you getting shot in a road rage incident for screwin' up an adjacent driver's toonz ;D

And be sure to check traffic laws against displaying certain colors of light on non-emergency vehicles. Especially showing red or blue toward the front.

What you need to do is to sit down and define all the individual groups of LED's in your project.

For the interior ligthning, how many LED's ? will they ned to change color? will colorchange be for all of the LED's or will you need individual color control over each LED?

The same for all other groups of LED''s, like tail ligths and so on.

Then you can start to look into how to control the individual groups /LED's, and the power requirements.

If you need large groups of LED's with the same color (not individual control over each LED) then it will be much easier to use some of the RGB LED strips available. They are as easy to conrtrol as a single LED, and you can avoid the wiring hell of using large amounts of individual LED's. It wil most likeƦy also be cheaper.

i used these: http://www.dealextreme.com/details.dx/sku.14965 in a mood light project and they are ok, and cheap. For your project these: http://www.dealextreme.com/details.dx/sku.16868 might be better.

@ Ran Talbott Im planning on changing them all individually.

Ive already checked out the laws, just doing it all mainly for the fun of it, gunna keep it legal when im actually driving though.

@ MikMo The exact number of leds, is not yet defined, as i dont have the car yet so im not sure exactly how many i would need, but it does have a large cabin. Color change, yes. Individual control, yes.

Thanks for the links, ill defiantly look into those.

Anyone have any suggestions as to how to power them? Being new to this stuff im not quite sure how one would create the optimal power level for them to operate at.

@ Richard Crowley Plexing idk, i've watched videos on it and such i just think it'd be easier (code side) to trigger them this way.