Gravity is a quick and easy way to turn the screen of your phone on or off automatically. It works using motion sensors that can tell when your phone is either placed down on the table or in your pocket. At that time, that app will switch your phone screen off. This will preserve battery life and keep you from having to fiddle with your device each time you move. You can use your voice to turn the phone screen back on. It is a great work around if you have broken the power or screen button on your phone.