When I am sleeping in certain locations, for example waiting for a vehicle in a sleeping room or airports, I want to make no noise to wake up to my alarm bell. There is a dilemma because the alarm bell makes some 100DB and it pretty much gets everyone angry every-now-and-then. How do you schedule your waking times in such positions as silently as possible?
I have tried an audio player in my ears but I tend to drop the ear parts while sleeping. I have also wondered about electric shock alarm clock but not sure whether something as silent may work.