The document describes a smartphone app called Phone Keeper that alerts users if they drop their phone. The app uses a phone's accelerometer to detect if it has fallen and hits the ground, then triggers an alarm after 3 seconds. It allows users to customize alarm sounds and volume. If the phone is later lost, its location could potentially be tracked using GPS or by detecting if it is on the same WiFi network as other devices. The app aims to help smartphone users avoid losing their phone. It may be marketed to insurance companies who could offer it for free to policyholders in order to reduce paid claims for lost phones.