Just Java™ 2

Some Light Relief—The Nerd Detection System

Most people are familiar with the little security decals that electronic and other high-value stores use to deter shoplifters. The sticker contains a metallic strip. Unless deactivated by a store cashier, the sticker sets off an alarm when carried past a detector at the store doors.

These security stickers are actually a form of antenna. The sticker detector sends out a weak RF signal between two posts through which shoppers will pass. It looks for a return signal at a specific frequency, which indicates that one of the stickers has entered the field between the posts.

All this theory was obvious to a couple of California Institute of Technology students Dwight Berg and Tom Capellari, who decided ...