For an artistic project, our hackerspace needs to make a very large, transparent touch panel (there will be no screen behind it). The required resolution is very low (on the order of 20x10 discrete positions) and the panel is very large (maybe 1.5mx1.5m). The panel will be installed in a vertical orientation, outside, in a sunny area, for several weeks if not years. Some regular maintenance is acceptable, and if things break we will be aware of this and be able to fix it without any appreciable impact.
We'd like to use glass instead of plexiglass for durability reasons, especially since we expect people to be touching it quite often. We'd also like not to have to push with loads of force in order to get the panel to respond.
I've scoured the intertubes, but haven't found anything at all. It seems that the touchscreen technology uses special coatings on glass. Considering the size and resolution, it seems to me reasonable to run some thin-guage wires between two panels of glass, but I'm not sure how that helps us.
For instance, maybe we can us such thin wire that we can bond it to the touch surface and effectively consider it a strain gauge. I'm not sure that this is sensitive enough, and temperature might wreak havoc on it.
Any ideas on how to do something like this?