[Lab] Touch sensitive/reactive windows

[Andrew O'Malley]

Hi gang,

I'm working on a an interactive light piece which is basically a large
tower covered in windows:
http://www.technoetc.net/imgs/urbana_2011_gameplay_2.png

Each window will be translucent acrylic, and illuminated from behind.
To provide interaction, I'd like each window to be touch sensitive.
I'd like to use a capacitive sensing approach, but not sure if this
will work until I do some experiments; I fear over such a large area
capacitive sensing will be very noisy.

In the meantime, I'd love to hear any suggestions anyone might have as
to how to detect users touching the windows.  I'd like to avoid having
to use little buttons beside each window or turning each window into a
mechanical switch -- since there are 100+ windows, I'm looking for a
solution that scales reasonably well.

Light or IR sensors might be an option, but I imagine will require a
great deal of calibration.  Does anyone have any experience sensing IR
reflections through translucent or tinted acrylic?

The piece is still in the design stage, so I'd love to hear your
suggestions/comments.

Thanks in advance for your consideration and suggestions,
Andrew