Product
Mobile Echo
Ground rover
An ECHO node on wheels. Driven out past the forward line, set down, and left listening.
It listens where nobody should be standing.
A fixed outpost hears whatever reaches it. A rover is put where the sound arrives first, and no one has to stay there with it.
It halts to listen.
Its own drive noise buries the thing it is listening for, so it stops before it listens. Move, halt, listen, report, move again.
