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.
Here’s an interesting WiiMote based project. [Mans] is a tennis fan, though a bit out of practice. With the tennis season coming to a rather climactic end, he got excited and wanted to brush up on his skills. He found the toss part of his serve to be very sloppy. Being a hacker, the first thing he thought was that there must be some way of tracking and graphing his toss so that he could improve it in an intelligent and controlled manner. The WiiMote seemed a perfect fit for this. Only a small modification was necessary, an external button wired to the internal “-” button. This switch is active while he’s holding the ball, and inactive when the ball is released. In this manner, he can track and chart his toss to find out exactly where he needs improvement. He uses [Johnny Chung Lee]’s code, with a small but unspecified modification to write the accelerometer data to a text file.
As he points out, this could be very usefull for any repetitive movement. Whith accelerometers getting cheaper and cheaper, there’s nothing stopping you from using multiple ones either. Imagine a golf rig to analyze your swing, Maybe a boxing rig that measured your hip twist and arm extension, or possibly a yoyo glove to tell you if your flick needs some help. Great job [Mans].