Anti-shoplifting Devices

Each year, businesses lose billions to shoplifting. To prevent this, most stores have invested in security. Common systems include electronic surveilance, security personel, and alarm systems. One of these systems, called the EM system, uses electromagnets to thwart shoplifters.

Electromagnetic (EM) System

The EM system, dominant in Europe, uses electromagnetic fields to prevent shoplifting. There are two parts to the system: the actual hardware (often placed at the exit of the store), and the tags on the merchandise. In a store using the EM system, everything is affixed with a small tag. Inside the tag is a ribbon or thin piece of metal, which allows magnetic force to travel through it easily. At the exit, there are two components of the scanner system, a transmitter and a receiver. The transmitter sends an electromagnetic field through the air to the receiver. The receiver interprets whatever reaches it to calculate which objects you are carrying out of the store. The receiver is looking for an activated tag, and if it senses one it will sound the alarm. Normally, the tags on your purchases are deactivated by the clerk at the register by a strong magnet. This deactivation causes the tag to be invisible to the sensors. However, if you walk through the sensors with an active tag, the receiver will sense the interruption that the tag causes in the magnetic field and sound the alarm.