Since my brother plays with it all the time, I always wondered how that little base reads the figures. The base just looks like it's normal white plastic.
According to the article Disney Infinity NFC figure video game begins shipping:
“Disney Infinity uses modern NFC technology to allow the figures to communicate with the game itself. Each figure has the ability to store data, and to operate on pretty much any platform,” Disney told NFC World.
NFC stands for Near Field Communication. NFC can connect through the air, so no direct contact is needed. Thus, the white plastic-like cover you see on the base is most likely just that: white plastic.
The inside of the figurines will look something like this: