Twin Tweaks ...
POB TERMINALS.
POB BOARD.
to the back of the robot. In our
endeavor to attach the arm is actually
where we stumbled upon our first
criticism of the POB bot — the extra
PWM ports may seem to invite the
addition of extra servos, but the board
itself does not provide ample places to
physically attach them.
A little ingenuity is easily able to
overcome this problem, but it just
stuck out to us just because these
good folks have made every other
thing about the robot so easy. Even
integrating the mechanical additions
into the programs was easy, especially
in RISBEE and POB Tools — all you
have to do is choose the appropriate
port number from a dropdown list
and you’re in business.
We also got our hands on a yaw
rate sensor, which we used mainly
because it had the unsocketed wires
that would be easiest to incorporate
into the free terminals on the bot’s
board. The POB Board includes both
digital and analog sensor inputs for your
hacking pleasure, and both are conveniently labeled in the documentation.
All it took to hook up the yaw
rate sensor was to place the power,
ground, and signal wires in the
appropriate slots and to tighten the
screws. Commands in C to read digital
and analog input are provided in the
documentation, but even the simple
RISBEE program had commands
capable of reading sensor input. Much
like for the motors, the appropriate
sensor would simply need to be
chosen from a dropdown list and you
were ready to go — a much easier
process for integrating sensors than
what we’ve come
across in other projects.
Why did we put on
the yaw rate sensor,
anyway? Well, it was
convenient, but we’re
sure that there would
be plenty of applications for a yaw rate
sensor on an intrepid
robot explorer. The yaw
rate sensor measures
the rate of change of
the yaw angle, which is
the angle of rotation
about the vertical axis. This has
obvious applications for navigation,
but usually it’s seen in aeronautics and
not on land-bound French robots. That
is not to say it wouldn’t be useful — it
could also potentially be used for
things like feedback on the physical
movements of the bot to ensure physical
stability if you’re, say, carrying a cumbersome load around some corners.
But hey, we’re just spitballing here.
Open Source,
Open Mind
POB MODIFIED.
Overall, we think the POB bot is
one of the most ambitious robotics kits
that we have ever received, but instead
of becoming a jack of all trades and
master of none, the POB robot is a
comprehensive robotics development
platform that can appeal to a wide
demographic of tinkerers. Its open
source philosophy is perfectly executed, and the robot provides a versatile
platform for programmers, electronics
whizzes, mechanical gurus, or any
combination thereof. And not only does
the POB robot make itself available to
tinkerers of all skill levels and interests,
but it also provides a great way for
everyone from hobbyists to professionals
to broaden their technical education.
Whether it be learning C, trying out
Linux for programming a robot, adding
your own custom sensor modules, or
just playing around, the POB robot
literally has something for everyone. SV
For more information, go to:
www.pob-technology.com. We would
like to extend a special thanks to
Philippe Kervizic for all his help.
78 SERVO 05.2008
