FIGURE 8
The competition I built Hot
Stuff for would have matches that
lasted three minutes long or until
one of the robots got knocked
out (whichever happened first).
Balancing battery power can be
tricky because if your battery is too
small, then you risk running out of
juice before the fight is over. If
your battery is too big, then you
are just packing around extra
weight you could be using
somewhere else. Figure 8 shows
me making a battery pack housing
that will space the cells apart to
keep them cooler.
Heat is an enemy to anything
electrical; in battery packs, extra
heat can cause the packs to run less
efficient and run out of juice faster.
To combat heat, I built cell spacers
out of polycarbonate to keep each
Sub C cell an 1/8 inch from one
another. I used Sanyo 2400 Sub C
sized Nickel Cadium battery cells to
power Hot Stuff because they are
FIGURE 11
FIGURE 14
28 SERVO 03.2010
FIGURE 9 FIGURE 10
lightweight, can source a lot of
power, and they can be charged
right in the robot. Figure 9 shows
the two battery packs finished and
ready to go in the robot.
Instead of rambling about how I
mounted all the internal parts by
bending this little piece of metal
here or welded that tab there, I’ll
just show you the photo with most
of the internals mounted (Figure
10). I’m using a paintball tank that
holds nine ounces of CO2 to power
the lifting arm. I run the CO2
through a regulator that takes the
900 or so PSI (pounds per square
inch) of pressure that’s in the bottle
and lowers it to 150 PSI.
There are two air cylinders in
the robot: a larger one to run the
lifting part of the arm and a smaller
one to run the grabbing part. Each
air cylinder is run by a valve hooked
to an R/C switch so I can control it
with a radio transmitter designed for
R/C airplanes.
In Figure 11, you can see
the robot stripped down to just
the frame. I hung it from my robot
lab rafters (Okay, okay, my garage
rafters) with a little piece of wire
and hit it with some red spray
paint. This part of the robot ended
up only weighing 13 pounds —
not to bad!
This was definitely going to be
a very animated robot because
every channel on the radio receiver
was full (see Figure 12)! It was
actually a really big pain to get all
the plugs to plug in at the same
time. (I guess the manufacturer
figured they would never all be
used at once.)
I started putting the robot
back together after the paint dried.
I used some black spray paint on
the drive pods (I really liked how it
all came out). In Figure 13, you
can see I started to wire up the
speed controller. This is one of the
most important parts of a fighting
FIGURE 12
FIGURE 15
FIGURE 13
FIGURE 16