Mapper button makes it easy to map custom actions to your volume buttons, home button, back and recent applications keys.
Assign custom actions to single presses, double tapes and long presses of the hardware buttons on your phone.
Volume buttons will work with the screen off if your device is rooted. Otherwise, the Map button does not work when the screen is off.
Some examples of keyboard mapping that you can do with the Map button:
Press volume -Long down to switch your flashlight
Double tap your home button to launch your favorite application
Long press your home button to turn off the screen