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50
4.9 Servo motor
industrial servo motors are also available, they are too expensive
for most hobby applications. In this book we work with inexpen-
sive and readily available hobby servo motors.
There are three wire leads to a servo motor. Two are for power, 4
to 6 V and ground. The third lead feeds a position-control signal to
the motor. The control signal is a variable-width pulse between 1.0
and 2.0 milliseconds (ms). A neutral, midrange positional pulse is
a 1.5-ms pulse. The pulse is sent 50 times a second (1 pulse every
20 ms or so) to the motor. This pulse signal will cause the shaft to lo-
cate itself at the midway position at ±45 degrees.
Team LRN
Chapter four
