The video assistant referee (VAR) has been a part of professional football in some capacity since at least 2016, with trials going back years before, but it hit the big time at the FIFA World Cup in 2018. Now, six years later, an extended version of it has cost Belgium a tie in its Euro 2024 match against Slovakia. The system registered the brush of Romelu Lukaku’s hand on the ball before it went into a goal.

And how did it do this? With a contact-sensor chip buried inside the Fussballliebe, as Adidas calls its official ball for Euro 2024. To piece together the explanations of Adidas and the chip’s maker, Kinexon, the ball contains a suspension system to hold an “inertial measurement unit (IMU) motion sensor” that operates on an ultra-wideband (UWB) at 500Hz. In other words, it tracks changes in its acceleration 500 times every second. It beams the data (speed, spin, trajectory, passes, shots, possession, etc.) to antennas around the pitch, which pass the data on to Kinexon’s software.

Adidas Fussballliebe for Euro 2024 - connected ball

Source: Adidas

Thanks to all this stuff, referees can now refer not only to the pitchside monitor but also to a version of “snicko” – a system borrowed from cricket, as The Sporting News explains. Snicko is a soundwave monitor that helps officials determine whether a bat has hit a ball. Adidas’ “Connected Ball Technology” does the same but measures contact instead of sound. The system can also triangulate between the ball and stadium cameras to judge whether players stray offside. Indeed, according to Adidas, Connected Ball Technology combines player-position data with AI and thereby “contributes to UEFA’s semi-automated offside technology.” So already not all of football’s officiating is human.

According to the Laws of the Game, kept by the International Football Association Board (IFAB), a VAR has “independent access to match footage” and “may assist the referee only in the event of a ‘clear and obvious error’ or ‘serious missed incident’” in relation to:

  • Goal/no goal
  • Penalty/no penalty
  • Direct red card (not second yellow card/caution)
  • Mistaken identity (when the referee cautions or sends off the wrong player of the offending team)

For now, though, a referee may not yield a decision to a VAR. It’s right there in principle 2 of the VAR rules.

Kinexon is offering the same service for handball as well.

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