Analog robot
An analog robot is a type of robot which uses analog circuitry to go toward a simple goal such as finding more light or responding to sound. The first real analog robot was invented in the 1940s by William Grey Walter. The name of these robots were ELSIE and ELMER (Electro Mechanical Robot). The original circuitry was developed using two vacuum tubes and a photocell to search and follow a light. Recently a kind of analog robots was developed by Mark Tilden.
Robot
In Renaissance Italy, Leonardo da Vinci (1452–1519) sketched plans for a humanoid robot around 1495. Da Vinci's notebooks, rediscovered in the 1950s, contained detailed drawings of a mechanical knight now known as Leonardo's robot, able to sit up, wave its arms and move its head and jaw. The design was probably based on anatomical research recorded in his "Vitruvian Man". It is not known whether he attempted to build it.