70 SERVO 08.2015
t’s a great time to be a roboticist. With so many
microcontroller board options like Arduino, Raspberry
Pi, and SparkFun RedBoard, it’s never been easier to
find a brain for your robot. However, a brain without a
good driving base is like Batman without Robin, or
Frodo Baggins without Samwise Gamgee. The folks at
Actobotics have the perfect solution for those looking for a
driving base that is easy to build, ripe for expansion, and
super affordable: the Runt Rovers.
Will the Runt Rovers be able to save the day for
roboticists stymied by the lack of a good driving base for
their microcontroller boards? With the help of two of the
Runt Rovers — the simple two-wheeled Sprout and the
more sophisticated six-wheeled Bogie — we were sure to
find out.
Everyone Loves an Origin Story
The Runt Rovers are an offshoot of the Actobotics
building system and are available through ServoCity. We
had our first exposure to Actobotics last time when we
worked with the system in conjunction with the Force servo
arm. The precision machined aluminum and distinctive hole
pattern gives the parts a stylish polish and a cool factor that
usually seems to evade plastic parts. The hole pattern
makes integrating servos into your designs so much easier.
With other kits, the small unusually spaced holes on
servo horns would rarely match up with larger structural
parts. The hole pattern on Actobotics parts are the perfect
fit for just about any servo attachment you could imagine,
but Actobotics is perfect for so much more than servos. The
system also features great parts like mounting brackets, hub
mounts, gears, and sprockets for use with motors, too.
After having such a positive first experience, we had
high hopes for the Runt Rovers. One difference between
the Runt Rovers and a lot of the other Actobotics parts is
immediately apparent. While they still sport some of the
familiar hole patterns, the structural parts for the Runt
Rovers are all plastic. This is not at all meant as a knock
against the kits. In fact, the thrifty construction is one of
their greatest virtues. The Runt Rovers are a lot gentler on
your wallet than slobbery Hooch to the pristine interior of
Turner’s car. The six different Runt Rovers range in price
from the bargain rate of about $16 for the simplest Runt,
to the still very bargain price of about $70 for the most
sophisticated Rover.
The six Runt Rovers are a veritable Justice League of
efficient robot design. The simplest kit is appropriately
named the Peewee. The smallest Runt (and we mean that
— the website shows a Coke™ can towering over it for
scale) has two wheels and two motors, and a simple
rectangular frame. The frame includes the distinctive hole
pattern in the center of the top body plate for expansion
with other Actobotics parts.
The next Runt is the Sprout, which is one of the ones
that we got our hands on. The Sprout is also a two-wheeler, but with a slightly larger frame and a few more
mounting points. One of the great things about the
ServoCity website is that on each page dedicated to the
Runt Rovers, the entire kit is shown laid out with the parts
identified so you know exactly what you’ll be getting.
The pages also feature tons of pictures with the Runts
in action, and some cool design suggestions with some
soda cans for scale. Just in case you can’t tell from the
pictures of the complete bot, if there’s one more set of
mounting holes on the bottom plate, the laid out parts give
you your answer.
The third Runt is Junior, which includes four wheels,
four motors, and a slightly bigger frame. The fourth Runt is
the Whippersnapper, which is also a four-wheeler. The
Whippersnapper has a taller profile than Junior — the main
body is big enough to house a standard servo sitting
upright. The fifth Runt is the boxy Half-Pint.
If the Runt Rovers were the Fantastic Four, Half-Pint
would be The Thing. The hefty bot provides enclosed
storage for all of your electronics, and numerous surfaces
Twin Tweaks
by Bryce Woolley and Evan Woolley
Go to www.servomagazine.com/index.php/magazine/
article/august2015_Twin Tweaks to comment on this article.
I
The Adventures of
Bogie and Sprout