envisioned would require substantially more power. I
viewed the promotional video ServoCity put out after the
release of the Agent 390 and I knew it could provide me
with the solution I was looking for (see Resources).
It is very stable and can carry a tremendous amount of
weight. Construction is a breeze and only requires a couple
of hand tools. The kit came with everything I needed which
greatly simplified the ordering process (Figure 2).
Track — The design of the track system right out of the
box has three wheels mounted in line on each side of the
body. Never able to leave good enough alone, I decided
that I preferred them mounted in a triangular fashion
(Figure 3). This, of course, meant that the tracks that were
included in the kit would no longer fit. Kyle — one of the
fantastic tech reps at ServoCity — helped me in securing the
longer tracks that my design required.
Although they were very close to being the perfect
length, I still had to adjust the height of my
upper wheels. This was accomplished by adding
a couple of thin aluminum spacers to get exactly
the right tension.
Batteries and Charger — One of the
primary restrictions regarding the mechanisms
was the amount of power available. Everything
would need to be run from batteries which
complicated the process.
The components required a mix of voltages
in order to operate. The motors running the track
system needed 12V, the servos needed 6V, and
the Banshee controller runs best on 9V. Granted,
I could have used a large 12V battery with the
appropriate regulators to meet each of these
needs. However, I wanted all the batteries and
electronics to be concealed in Jarvis’ body.
Separate batteries allowed me to place them in
the narrow body compartment and keep them
out of sight. It also allowed me to utilize some
batteries I already had on hand.
I wanted to maximize the run time between
charging, so high capacity batteries were a must.
ServoCity had the 12V solution with their 12V
6,000 mAh Li-Ion power bank battery. It does not
require a charger as you simply use the provided
unit. For the 6V supplies, I chose to go with a pair
of 10,000 mAh rechargeable NiMH batteries from
RobotShop (see Resources). Splitting the servos
between the two of these would provide the
extended operating time I was looking for.
Supplying the power-hungry servos with enough juice was a
major concern, but these batteries are up to the challenge!
The one issue I did have was that the battery charger I
had was not able to charge these. The Hitec X2 AC Plus 2
port multi-charger (see Resources) provided the necessary
punch to keep both batteries in tip-top shape. This fantastic
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SERVO 09.2016 11
Figure 4. Charging stations at the ready.
Figure 3. The track system sets Jarvis free!
Figure 2. It all starts with the right Actobotics platform.