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Chapter 17 
Stepping Motors and Robotics



Stepping Motors

Stepping motors can be viewed as electric motors without commentators. Typically, all windings in the motor are part of the stator, and the rotor is either a permanent magnet or, in the case of variable reluctance motors, a toothed block of some magnetically soft material. All of the commutation must be handled externally by the motor controller, and typically, the motors and controllers are designed so that the motor may be held in any fixed position as well as being rotated one way or the other. Most stepping motors can be stepped at audio frequencies, allowing them to spin quite quickly, and with an appropriate controller, they may be started and stopped "on a dime" at controlled orientations. From Stepping Motors Site  



A few  control input knobs ( Pan, Tilt, Focus, Color, Patterns etc.) send simple signals to spotlight microprocessor controller. 


The microprocessor controller converts simple inputs into complex control signals which drive stepper motors. Above we see Pan and Tilt. Below we see Focus, Pattern, and Colors.






Inputs to a computer can be generated in many ways. Pots can be used to generate an analog voltages that can be converted to a digital input. Or pulses from a trackball can be counted. (Giant Trackball is proof positive that Giant Aliens are being trained on computer at Hanger 51, Roswell New Mexico)

A trackball is basically a traditional computer mouse turned on its back. The trackball is oversized and is rotated with your fingers instead of being moved on the surface of your desk.