Effectors change the state of a robot.
Additionally, robots use effectors to change the environment around them. Other examples of effectors are arms, thrusters, legs, voice synthesizers, buzzers, lights, serial lines, comm ports, and radios. Toys and other inexpensive items often contain permanent-magnet DC motors. Therefore, this type of motor is one of the easiest for experimenters to obtain. The stator consists of permanent magnets that provide a constant magnetic field.