I'm working on a project (first time working with both LEDs and Arduino) which involves a 24x24 array of LEDs. The array is made up of a 3x3 grid of 8x8 LEDs, each driven by a MAX7219. The array is being installed in a wearable helmet, and needs to be portable. It also needs to be able to last for at least 2-4 hours on a single charge, ideally more. Will something like this rechargeable battery shield do the trick? http://www.liquidware.com/shop/show/BPM/Mega+Backpack
Also, as this is the first time I'm attempting to work with these materials, I'm really not sure which Arduino to buy. The final product should be able to display different animations (no more than ~300 individual frames). I'd also like to have an audio input that can select different frames to display based on input volume levels.
Any guidance on this project would be very appreciated. The Arduino platform seems to have limitless potential, and I can't wait to see this whole thing completed.