1, Monitor the distance between device and phone, trigger alert when device is lost or found. Location can be stored in app when lost or found event is triggerd.
2, When user double click or long press device button, the app will send SMS for help. The SMS message can contain a url if location feature is enabled. Receiver can view sender's location in google map in web browser after clicking the url.
3, Selfie.
4, Fix minor errors.