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An actuator is a component of a machine that is responsible for moving or controlling a mechanism or system. An actuator requires a control signal and a source of energy. 

A sensor is a device that detects and responds to some type of input from the physical environment. The specific input could be light, heat, motion, moisture, pressure, or any one of a great number of other  factors.

Controls are the devices or mechanisms installed or instituted to guide or regulate the activities or operation of an apparatus, machine, or system.