The app evaluates the acceleration of the mobile phone
when the acceleration is above a specific value or the phone is in free fall it sends a text to a phone number (and they will cost you money, if the texts are not included in your mobile plan). We are not charging you for the texts, are standard text messages
Disclaimer: I believe that the app is going to work but a bug is always possible. Do not use this app as safety application/device, it is only for fun.
The app requires all the permissions for the device localization (with wifi, internet, gps etc) and the permission to send standard text messages to the mobile number that you specify (the phone company will charge you for that if not included in your plan)