Re: Nearest I can tell, it's magic.
It seems so. "Harry, we're getting a .2 undervolt reading on your watch battery. You may want to replace it when you get back."
"George, your bladder is getting full. The Docs say to plan on a pee in about 12 minutes."
"Sergei, there is a differential in the voltage across your eyeglass lenses indicating they are dirty. Korolyov says to clean them or else! They asked me to remind you it's a long walk home."