“You’re telling me I have to go to concerts without fun light-up wristbands after this?” wrote one Taylor Swift fan on TikTok after the US singer’s concert in Cardiff earlier this summer.

The reason for that was the illuminated wristbands worn by concert-goers. Attendees of Coldplay concerts across the world are allotted a xyloband as part of their entry to the show, a move which ...

From arena-sized concerts like Taylor Swift or Coldplay to the Super Bowl halftime ... to see the tech behind the wristbands. Photo illustration: Madeline Marshall ...