Spider-Signal

The Spider-Signal is a light emitted projector from Spider-Man's Web-Shooters.

Captain America: Civil War
Peter Parker closely examined the new equipment that Tony Stark designed for him once he returned to his home after battling against Captain America and his team.

Parker accidentally activated a new function in his Web-Shooters while checking them when his aunt May Parker entered into his room to take care of his blackened eye, forcing Parker to hide the device behind a cushion. Once she left, he noticed a red light beam being projected from the Web-Shooter and looked at the roof to notice a signal very similar to the mask of his new costume.

Trivia

 * In the comics, the Spider-Signal is emitted from Spider-Man's belt instead of his Web-Shooters.