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.
Automaton
The automata in the Hellenistic world were intended as tools, toys, religious idols, or prototypes for demonstrating basic scientific principles. Numerous water powered automata were built by Ktesibios, a Greek inventor and the first head of the Great Library of Alexandria, for example he ""used water to sound a whistle and make a model owl move. He had invented the world's first "cuckoo" clock"". This tradition continued in Alexandria with inventors such as the Greek mathematician Hero of Alexandria (sometimes known as Heron), whose writings on hydraulics, pneumatics, and mechanics described siphons, a fire engine, a water organ, the aeolipile, and a programmable cart.