Soccer balls perform best when filled with the correct amount of air, so the people at Egos Ventures came up with a way to monitor soccer ball inflation through a soccer app called BallTune.
Just like instruments, soccer balls need to be kept "in tune" and up to standards, especially when they are needed in professional settings like the FIFA World Cup. The BallTune app tells you if a match ball needs air just by listening to it bounce. All you need to do is drop your ball onto a hard surface and point your phone towards it. The app will then record a video and analyze the sound and frequency of the ball's bounces to determine the its PSI.
The game-improving app is available for iOS and Android and usually costs $2, but for the duration of the World Cup it's free.