A dead man's switch (see alternative names) is a switch that is designed to be activated or deactivated if the human operator becomes incapacitated, such as through death, loss of consciousness, or being bodily removed from control.
How do you make a dead man's switch?
https://www.youtube.com/watch?v=b6LoNZXkwSA
What is another name for a dead man switch?
dead man's brake dead man's control
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dead man's handle dead man's pedal
dead man's trigger kill switch
live-man switch vigilance control