how holes were cut for the drive
motors, as well as the two drive
wheels. The fore and aft casters allow
quick manueverability with the
differential steering system. You might
desire two levels (platforms) on which
to place a computer, Kinect sensor,
video cameras, and other sensors.
Most people like to place their
batteries at the lowest point for
stability, such as below the bottom
level in the Parallax Eddie. This is fine
for heavy gelled electrolyte lead-acid
batteries, but lithium-ion and
especially lithium polymer batteries
should be placed in a higher, easily
So, we’ve talked about a few
different types of bases for robots
that are offered by several good robot
manufacturers, but it can be easy to
build your own. For smaller robots, it
makes sense to use an already-built
platform, but you can save money by
bases for larger robots yourself.
We have already seen that plywood
can make a pretty good platform —
even if you cannot find the quality
plywood that Parallax used in their
initial large bases.
All of my earliest robots were
made of plywood or galvanized steel
HVAC ducting. Depending on the
overall size of your design, anything
from 1/4” to 1” plywood (with both
sides smooth finished) will do.
In later years, I preferred metal
bases for larger robots, and have used
1/8” and 1/4” 6061-T6 aluminum for
most of my creations.
If you are limited to just thin
metal stock, a great design concept is
to use Actobotics 1-1/2” x 1-1/2”
aluminum channel as shown in Figure
8 as side rails to strengthen the
flexible sheet metal, as well as for
mounting motors and wheels.
You can also use shorter channels
for the front and back, as there are
10 lengths to choose from.
The advantage to these channels
over stock “L” or aluminum channels
at hardware stores is the unique hole
patterns that fit so many ServoCity
products and brackets. The robot
shown in Figure 9 was
built by Robert Beatty
and his daughters, and
was made entirely from
Structures for Your
For many years, I had access to
large power metal shears for cutting
and metal brakes for bending metal
sheets. I no longer have this access
like many other people, so must resort
to purchasing metal pieces already
supplied in the sizes required. Of
SERVO 06.2015 79
Figure 8. The 1.5” x 1.5” aluminum
channel stock from ServoCity.
Figure 11. Milwaukie Sawzall cutting steel channel.
Figure 9. Robot built by Robert Beatty
and his daughters with