increase in resolution that
provides you with the
needed data for
determining the direction
of travel of your robot.
and Tilt Linear
So, let’s build
something with encoders.
You know, photography
has some great robotic
opportunities that would
benefit from attaching
encoders to drive motors.
In fact, with just a couple
of encoders and several
small gearmotors, a
complete camera drive
system can be built that will rival some of Hollywood’s
finest film production systems.
While not quite up to Lucasfilm standards, this project
is ideal for remote camera operation, as well as filming
smooth transitions between different camera angles. Stated
in a more formal project parlance: Let’s build an automated
pan and tilt linear slide for cameras like the one in Figure 1.
While a mild (or wild) shopping spree at the Actobotics
webstore will provide you with everything needed for
building this project, there is one magic ingredient that is
hidden deep inside the store. This marvelous part is simply
labeled “Potentiometer Board A.” Huzzah! This is not just
some simple pot board. This, my friends, is an encoder in
Hidden deep inside the product description for Part
Number 605124 shown in Figure 2A and Figure 2B is this
curious comment: “... creating a controller with a remote
potentiometer can be done using
this board and a controller that
accepts an analog input.” Although
that little nugget of information is
a bit difficult to decipher, the
bottom line is that this part can be
used as a rotary encoder —
provided you can find a motor
controller with the capability of
reading this encoder’s pulses.
Armed with this new
interpretation of creating a rotary
encoder from this board, we can
locate the second missing link for
our encoder project elsewhere on
the Actobotics site. If Potentiometer Board A is the “magic
ingredient” for our project, then the RoboClaw 2x7A Motor
Controller (Part No. 605095) in Figure 3 is the secret sauce
for this recipe. Not only do RoboClaw motor controllers
provide the power to move your project, they are also
capable of reading dual quadrature encoders at a resolution
of over 19 million pulses per second! Likewise, simpler
absolute encoders are supported, as well as ... wait for it ...
So, our entire project is almost
complete with two RoboClaw 2x7A
motor controllers and two
potentiometer board “As.” Now,
we just have to add “the other
bits” and we’ll have a complete
camera control system. The Parts
List lists all of the Actobotics parts
you will need for building your
own automated pan and tilt linear
slide for your camera. Granted, this
parts list specifies a GoPro camera
mount, but any mount plus
camera combination up to two
By Dave Prochnow
SERVO 03.2016 43
Figure 1. The pan/tilt motors along with
the camera mount.
Figure 3. The RoboClaw 2x7A motor controller.
Figure 2A. One of the green potentiometer board
As is attached to the pan motor.
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