This is a script that will hook into windows event system and add a callback function to send keyboad events to unity even when unity doesnt have focus.
Place the script anywhere in your assets folder and it will take care of the rest.
// Keycodes are stored in GlobalKeyCode // e.g. GlobalKeyCode.LEFT is the left arrow key // GetKey GlobalInput.GetKey( GlobalKeyCode ); // Works the same as Input.GetKey( KeyCode ) // Will output TRUE if the key in the parentheses is being held // GetKeyDown GlobalInput.GetKeyDown( GlobalKeyCode ); // Works the same as Input.GetKeyDown( KeyCode ) // Will output TRUE only ONCE if the key in the parentheses is being held // GetKeyUp GlobalInput.GetKeyUp( GlobalKeyCode ); // Works the same as Input.GetKeyUp( KeyCode ) // Will output TRUE only ONCE when the key in the parentheses is lifted after being pressed