Any robotic system that was built before the advent of modern electronics could be considered a non-silicon robot. Automation has been a significant component of industry for over 150 years and pre-transistor control systems of the 1930s and 1940s were fairly sophisticated. These control methods are largely forgotten. Such systems use pneumatic, mechanical and electric control systems.
With some notable early exceptions (W. Grey Walter), in the modern era, non-silicon robots have been mainly confined to obscure research and purely teleoperated robots and have received relatively little attention. However, this is changing with the development of non-traditional computing technologies such as molecular computing (unconventional computing and non-silicon computing).