control 400 rgb leds (w/dmx) ?


First of all, i'm new there so hello and greetingz for the arduino creator as well as the community. Well, not sure i'm posting in good area but couldn't figure the right place for my question.

Actually, i've a project in mind, i have the picture (in my head) about how does it looks but i'm not sure how to realize it. Basically, i want to control a lamp made of 400 ping pongs ball organised in a sphere. In each ping pong ball, there'll be an rgb led.

What i'd like to achieve is to be able to control remotly from a box made of an griffin powerplate (which will control color brightness and so on) and a switch or rotary button to swtich between different animation pattern.

I'm thinking about implementing it with the dmx protocol, but i'm not sure.

Does arduino could be used for that ? Take the input from powerplate and another device send them through wifi to another arduino board which will control 400 rgb leds ? (Open DMX maybe ???)

I feel a little bit lost with it, so any help would be greatly appreciated. I'm a beginner with electronics, have some developper experience.

Regards, anchnk

I think that controlling 400x3 leds in real time + decoding the DMX protocol + wifi (or another wireless) transmission might be a little bit too much for one arduino.
To update your array of leds, you’ll need to send 1200 byte = 9600 bits if you don’t use any “compression” method I don’t know the bauds rates of ZigBee or Bluetooth transmissions but at 9600bauds, you’ll only have 1 fps. You’ll need at least 240.000 bauds for 25fps… Then, you’ll have to process those datas and send them to let’s say 75 TLC5940 driver chips (16 PWM out by chip > 1200/16 = 75) in the non multiplexed scheme.
Maybe it possible, but I doubt only one arduino is enough.

Reality check! ::)

Four hundred is a very big number. Let's look at the LED current. At 20mA per LED three LEDs (RGB) times 400 gives an LED current of 24 Amps!. This sort of current requirement alone takes it out of the realm of a simple exercise for a beginner and into a project that requires some real engineering. And that's before you consider the cost.

Scale you ambitions down and go for a 4 LED system, you will have your work cut out with that.

Both thx for these valuable informations.

I agree it's a bit too much ambitious for a beginner and for a personnal (off-work) project too. I was pretty sure that was too much for a simple arduino board but if it was possible, it'd have been the cheapest solution.

I didn't took in account at all the LED current problem which is a really good point.

You are right, i'll start with a 4 RGB Led system and see what is possible. It must be hard to achieve something neat with 1200 wires out from 400 RGB leds as a first electronic project.

If you have some pointers about some device concerning current manadgement or another piece of hardware i should be aware of, let me know because your hints are really time saving and so helpful.

So, again, thx a lot !

It would be nice for to be able to get a hold of some of these types of add on chips ie TLC5940 In Australia, I can't find a single distributor, I work at an electronics place, we get wholesale from jaycar, altronics, and so many different places it's not funny, they don't have a large collection of IC's

If someone knows where we can order some in Australia that'd be great


digikey or futurlec doesn't ship to australia?