The [Fédération Internationale de Football Association] is joining the growing list of professional sports that is adopting technological means in an attempt to help the human referees. After a botched call in 2010 the organization called for a system that would work day or night, with 100% accuracy and the ability to report to the Refs in less than 1 second. The applicants have been weeded out and it comes down to two systems, both of which use a piece of personal hardware we’re quite familiar with. [Fe80], who sent in the tip, recognized the TI Chronos eZ430 watch in the image above.
The two systems both use the watch as an interface, but work very differently. The first, called GoalRef, uses a sensor suspended inside the ball. This detects a magnetic field made up by the goal posts. We’d guess it’s an inductance sensor that is triggered when it passes a coil in the goal posts (we didn’t find much in the way of technical info so please do your own speculation in the comments). The second system is very familiar. It’s the Hawkeye camera system used by the APT (Tennis) in all the major tournaments.