Cheers dhenry, I'll have a read.
CR: they're sensitive up to 820nm, from around 300, so more than enough.
Thanks for the input cr0sh, I'd need a hell of a lot more than that though I think, I suppose the other alternative is to use multiple arduino boards, each diode, or whatever I decide to end up using will act as a pixel to create a image/video - depending on which route I go down, hence why more is better.
I found out there is an electronics department which is combined with the computer science department at a different campus as part of my uni so going to try and have a meeting with them see if they can help me with the project, but cheers for all the input - it gives me an excellent start!