There is no setup needed to use the Arduino Wire library, as it comes installed in the Arduino IDE. You can find the library files by navigating to Arduino/Libraries/Wire, but it's not recommended ...

An Arduino can measure time, a coil and a resistor will create a delay proportional to the circuit values, and metal around the coil will change the coil’s inductance.

Well tech tinkerer Joe Desbonnet has whipped up what he dubs "poor man's NFC" using an Arduino, some magnet wire, and any compass-equipped Android smartphone (which is almost all of them).