[matheist]

I use a vibrating alarm on my cell phone under my pillow (off to the side, not directly under my head).

I sleep with both earplugs and a white noise machine, so an audio-based alarm can't work for me. (City living! the garbage trucks come for some house on the block on every weeknight.)

I still have traumatic memories of my radio-alarm-tuned-to-static waking me up for high school, and when the garbage trucks used to wake me up before I started with earplugs and noise machine, I'd wake up with a jolt of adrenaline, so I relate to your "gunshot" comment. The vibrating alarm doesn't trigger that for me.