Twin Tweaks ...
ROV CAMERA AND LIGHT.
attention that land bound bots find
unnecessary — waterproofing. The
manual suggests casting the lights
and camera in resin and gives detailed
instructions on how to do just that,
but our CCD camera and LED cluster
came already cast in the kit. We didn’t
mind the assistance, and we set about
tackling the next steps.
The ROV-in-a-box is a humble
robot equipped with only the
essentials: three motors, the camera,
and the lights. Mounting these
essentials to the frame is also done
with PVC bits. After just a few quick
cuts, the ROV was starting to look like
a real robot, but the real test was still
ahead — wiring it all up.
We have to say that up until the
wiring of the control box, we were
TSUKASA (L) AND ERIC (R) WORK
ON THE TETHER.
consistently impressed with the
quality of the parts included in
the kit and the clarity of the
instructions that helped to put
it all together. Perhaps this
initial awesomeness created a
harsher contrast than was
warranted when it came to
wiring the robot, but we have
to say at times it became
downright inelegant. For the
most part, the control box
was fine — each thruster was
controlled with a double pole
double throw (DPDT) switch,
the main power was controlled with a
single pole single throw (SPST) rocker
switch, and the kit even came with
labels for all of the switches to denote
which motor they controlled. All of
the switches even went into a nifty
control box that looked downright
sleek, and all of this was quite nice.
The problem, we suppose, was in
the wires.
We have nothing against heavy
gauge wires. They are great for when
you are pulling a lot of amps and their
beefiness makes them generally easier
to solder than super thin wires. When
you have more than three 16 gauge
wires going to one leg of a switch in
a crowded control box, then size can
become a problem. This might not
seem so difficult if you are properly
prepared — you can twist the ends of
the wires together and save time and
energy by soldering once where you
would have had to solder many times.
The manual, however, goes through the
connections one wire at a time, and
after the fourth wire going to the same
switch leg, you begin to wonder if you’re
soldering a control box or a clown car.
The large gauge wires are also stiffer
and when it came time to close the
control box, it was not exactly fun.
The problem with the wires
could have been minimized if the
instructions had warned about the
overpopulated legs beforehand, but
instead they go through connection
by connection and by the time you
realize there’s going to be a problem,
it’s already too late. Some of the TBP
team members were learning how to
solder on the ROV control box, and
these complications gave them the
opportunity to learn how to desolder.
For all of the grief that the size
of the wires gave us, the actual
electronics of the ROV were elegantly
straightforward. The relatively simple
wiring even made it easy for us to
track down an electrical problem
using a multimeter. Our ROV only
seemed to work intermittently, and
the rocker switch did not seem to
control the main power. When we
had first installed the fuse, we had
not done it correctly; but with the
addition of a spring, everything was
in top shape. Even with the ROV
effectively finished, the manual
continues to be useful. The manual
includes an electrical schematic for
the robot and an exhaustively
comprehensive parts list that details
the cost and vendor for every item in
the kit. We would like to give some
well earned kudos to the authors of
the manual, because they really did a
top notch job. Congrats!
ROV CONTROL BOX.
Overcoming
Hydrophobia
The ROV-in-a-box is an elegantly
simple machine. Everything went
together so easily that it seemed that
there had to be more to it. There was
actually more to it — waterproofing. In
truth, though, there was not that much
waterproofing to be done. The resin
castings kept the camera and lights
safe, and the motors were designed
for underwater applications (perhaps
pumping, as the 500 GPH label might
fanatically suggest). The only critical
16 SERVO 08.2008
