Magnetic Installation idea

Hello everyone.

I am undertaking a project whereby I intend to create a music installation based on iron filings and magnetic fields. I will set up a space where the user can interact with a surface of iron filings using magnets. The position of the iron filings will be influenced by the magnets and so it will be possible to track the movement of the particles in Jitter using a camera input, and then use the obtained video information to control a piece of music using Max/MSP.

I have some ideas for the piece. I thought of revolving the code around a matrix that is a controller for sample playback, effects levels, events, fades, etc. I'd need some input for the matrix object so that it could turn cells on/off based on the current camera input. I think I could use colour information or position to gather some integers I could extract to control a matrix, but i'm not entirely sure how to go about it.

One aesthetic idea was to allow a user to sprinkle powder paints onto the same surface as the iron filings. I have three different coloured paints. As the iron filings were moved, they would brush past the powder paint and leave a kind of trail behind, hopefully. This would mean there would be varied colour information, and spread of the colour would vary too.

I'm wondering if anyone knows of any tips, patches or externals that may prove useful for a project of this nature. Any suggestions greatly appreciated.

Many thanks
Stuart