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.
History of robots
The first post-classical society known to construct automata were the Byzantines. They inherented the knowledge on automata from the Alexandrians und developed it further to build water clocks with gear mechanisms, such as for example described by Procopius about 510. The knowledge on how to construct automata was passed on to the Arabs. Harun al-Rashid built water clocks with complicated hydraulic jacks and moving human figures. One such clocks was gifted to Charlemagne, King of the Franks, in 807. Arab engineers such as Banu Musa and Al-Jazari published treatise on hydraulics and further advanced the art of water clocks. The segmental gears described in "The Book of Knowledge of Ingenious Mechanical Devices", published by Al-Jazari shortly before his death in 1206, appeared 100 years later in the most advanced European clocks. Al-Jazari also published instructions on the construction of humanoid automata.