A Linux-powered microwave oven

Neither have I. But my father-in-law had "the shakes" - his hands only did approximately what he asked them to. Buttons are often unforgiving if you hit the wrong one or press too many times. His voice worked perfectly well though.
And the other commenter who carries a bowl of soup with two hands... imagine the solenoid which usually locks the door being given a reverse current when you say "Open Sesame" so that the door swings gently open.