SayVU is one of the many Israeli security products and services deployed in Rio to protect the Olympic Games. It enables a user to send a distress signal to an emergency hotline even if a phone is locked. The message can be sent by shaking the device, tapping the camera button, or speaking into the phone.
https://aabgu.org/bgu-student-startup-used-at-rio-olympics/
http://www.timesofisrael.com/israeli-emergency-tech-aims-to-make-rio-attendees-safer/