Assuming you mean press the ball again to send the start Activity again this can never happen as this will mean some Devises in the Activity will be out of sync. Also pressing it when in an Activity already has a function, saved Favourites and Macros come up on screen, if nothing happens you don't have any yet.
The best way to solve your problem is to allocate a spare button, long press or create a Favourite within the Activity for the Power Button of the projector then when it goes to sleep just press this to wake it up.