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 notifies users so they can find a lost phone quickly before it is too late. The app allows customizing alarm sounds and volume. It also includes features to locate a lost phone on a map and set alarms on other devices on the same WiFi network. The developers plan to market the app to insurance companies who could offer it for free to policyholders to reduce lost phone claims.