Max LED's and power?

Hi all,

Brand new to this, so bear with me.

I've had an idea and I wish to explore if it's possible. I've done some searching and found some good resources on powering and controlling multiple LED's, lots on or off, cycling colours etc. I've not found as yet if it's possible to have an array of LED's lets say 400 with granular control, each LED would be one colour but any one could be on or off...

Each LED loosely represents a location, I want to be able to turn an LED on or off based on some conditions. So they won't all be on at the same time. At peaks maybe 50 per second would be on.

Is this possible a. in arduino b. easily (depends on experience I know)

I'm assuming I'll be powering the LEDs off board turning on and off with a transistor/controller as the board itself won't have the raw power. As I say, totally new to this, it's an idea, wondering if it would practically work. I don't know what the control limits are of the chipset.

I'm currently looking at http://www.arduino.cc/en/Tutorial/ShiftOut and skimming the Start kit manual...

Thanks in advance... :)

If you want proportional control the you will have to use some sort of controller chip like the TLC5940. This will control 16 LEDs and you can multiplex them in a 4:1 ratio as in this project:- http://www.thebox.myzen.co.uk/Hardware/Mini_Monome.html This gives you 4096 steps of brightness for each LED.

Something like the MAX695 will drive 128 LEDs and give 16 levels of brightness but only in blocks of 4X4 LEDs. That is each block will have all the LEDs the same brightness.

However don't start off with a 400 LED matrix start off with a 16 LED one, you will find that takes a lot of wiring up and you might want to scale back your ambition.