Safety Unit is a security ring linked to a mobile app. The ring will be provided with a camera and a button with different ways to be pressed, so a victim will be able to: film, call the police or call an ambulance. In addition, it will emit a sound (optional) to warn other people that the user is in danger.
The mobile app will notify other users (within a certain perimeter) that an inccident has happened. So they can see in a map where the victim is and if someone has already call the police or emergency services. With that information, the users can film or take pictures if they are close enough (files what are sent to a police server, not saved in the user´s phones). They can also call the police or emergency services and report the incident. Furthermore, if they feel not in danger they can directly help the victim or try to catch the criminal, as they are now connected to other users they can gather to help.
If you feel like knowing more about the whole UX/UI process, don´t hesitate to read my article in the following link: Design Thinking: Improving Citizen Security. Part I.