galvanized wire as material to construct a sensor matrix
It's a mild steel wire coated with zinc to prevent rust and corrosion. Unless you put it in a special furnace, it will not melt. It's a metal, so not bad at conducting electricity, unless you'll be laying miles of it... in which case copper is better. It is, however, difficult to solder to, and somewhat rigid. Also, the softer zinc coating may wear off if handled a lot, in which case the steel will rust. I suggest putting a coat of varnish when it is new to preserve the zinc coating.

Enameled copper wire (magnet wire) is a possible alternative, but is more difficult to obtain. Bare copper wire may also be available at the hardware store. 

Also, brass wire is an alternative, may be available at the hardware store, stiff, resists abrasion, corrodes less than copper, not too difficult to work, looks good, easy to solder to... I use it all the time (for making contacts and springs).

Another alternative is aluminum wire/sheet, but it cannot be soldered to... although it is cheap, comes in a variety of shapes and sizes, and is soft and easy to work with with simple tools. Connections would have to be riveted with aluminum rivets (which are easy to make from wire).