Having had experience trying to wake teenagers, the "Sonic Bomb Alarm Clock with Bed Shaker" (still selling on Amazon) is highly effective at causing teenagers to literally fly out of the room.

And this was at the request of said teenager, who really didn't want to be late but just couldn't wake up the normal way.

Of course, it woke everyone in the house, too, but it was super effective.

We eventually coupled it with a medium sized pneumatic air raid horn hack on an independent clock for even more impact. One neighbor wanted the timing rolled forward about 10 minutes or so, so it could accommodate his schedule as well.

The other neighbor was an older deaf lady, so no trauma there.