Figure from ROBOT, Moravec, Oxford, 1998, Chapter 2: Caution! Robot Vehicle!, page 18
Elsie the robot

1950-Dr. W. Grey Walter operates on one of his light-seeking tortoises
When ``Elsie'' is fully assembled, the bump-sensing switch at the top of the mechanism supports a protective shell, seen in the background.

From The Robot Book, Richard Pawson, Windward, 1985, p.14.