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.
George (robot)
In 1949 Tony Sale used the scrap metal from a grounded Wellington bomber to build a simple 6-feet humanoid robot he named George. The construction cost for the robot was about £15. Actually, this robot could be considered George Mark IV, as Sale already built a very basic robot in his parent's garage when he was 12 and named it George, plus two later versions.