Small, dedicated boards drive servomotors
without (or with) programming.
By Robert H. Walker
Servomotors do the heavy lifting in countless robotic,
animatronic, and other projects, and because they’re so
visible, it’s easy to overlook the role played behind the
scenes by their controllers. Your choice of servos for any
given project will boil down to the mechanical force you
require and the physical size you have room for, and you
can buy servos that range from very small to large and
powerful. But with servo controllers, the selection criteria
are more complex, and include the following questions:
» How many servomotors will you need
» Will activation be triggered manually
or by an external signal?
» What’s the nature of the triggering
signal (continuous, momentary, etc.)?
» Do you need programmable onboard memory?
Meanwhile, you can also program
a general-purpose microcontroller to
control servos. For example, Arduino’s
built-in servo library lets you control
2 servos from your code by connecting
their signal wires to I/O pins 9 and 10.
This is good for some projects and a nice
way to experiment, but for other uses,
dedicated servo controllers offer a simpler, smaller, and more elegant solution.
Robert H. Walker has authored numerous articles about model train control and helped pioneer the hobby’s use of
servomechanisms. He holds a master’s degree in electrical engineering and has been awarded five U.S. patents in
the field of radio communications.
Photo illustration by Gregory Hayes and Jason Babler
112 Make: makezine.com/31