There’s no need to charge batteries or lug a lead-acid
battery around. The Pool Bot 9V power is easy to carry and
easy to connect. Likewise, the amount of cable needed for
a lightweight 9V ROV is reduced to a neatly braided twist
of six 22-gauge wires. The length of these wires is
determined by the distance from shore to the target depth
inside the swimming pool. Generally speaking, a spool of
20 foot pencil diameter wire should be sufficient for most
Before you start construction of Pool Bot, make sure
that you have two empty and clean olive jars. While olive
jars aren’t mandatory (i.e., bacon bits, pickled peppers, etc.
are good alternatives), any clear glass cylindrical household
grocery jar will work. If glass jars are a concern for you, use
plastic soda bottles with weight added inside (sand, rocks,
etc.) instead. Just make sure that both jars (or plastic
bottles) are identical in size, weight, etc., and the lids can
create an airtight seal. You can test this requirement by
loading each jar with several heavy metal washers,
attaching the lids, and holding the jars under water for
several minutes. If you don’t see any air bubbles
streaming from the lid and the contents are still dry after
this water test, the jar can be used for Pool Bot.
(If you’re having trouble emptying an olive jar, make
a batch or three of ROV Martinis (e.g., 1-2/3 ounces gin,
1/3 ounce dry vermouth, dash of black strap rum, and
several large olives; shaken not stirred, then add olive
One final precaution: Even though the power supply
is a modest 9V system, water is still a deadly enemy of
Pool Bot’s electrical motors. Make absolutely sure that the
entire ROV propulsion system, camera system, and LED
lighting system are completely and thoroughly
waterproof. Liberal applications of waterproof silicone
sealant to every critical opening, joint, and conduit is
essential. Also, watch for breaks in the wiring insulation;
one crack can doom the ROV. Frayed, cracked, and
abraded wiring should be immediately replaced.
Pool Bot Frame
1. Place the lids on the two jars and lay them parallel to
each other on your workbench; glass ends forward.
While the distance between the jars is not critical, this
space will determine the overall size of Pool Bot.
2. Loosely lay the Schedule 40 tees and elbows around the
jars following the layout in the frame photograph.
3. Use a hacksaw to cut the Schedule 40 pipe into short
pieces for connecting the tees and elbows together. A
press-fit construction is all that is necessary. If the final
frame is too wobbly or loose, you can opt to glue all of
the joints. Remember that gluing Pool Bot’s frame
together will make it impossible to disassemble for
storage. The pipe lengths used here are: nine two inch
pieces and eight three inch pieces, with one two inch
piece used for the ROV keel and the eight remaining
pieces inserted into all open upright elbows and tees.
4. Follow the manufacturer’s assembly instructions for
building the Pool Bot motors. During assembly, do not
attach the rudder (part #A6), suction cup and holder
(part #A3), and the jumper plate to any of the motors.
5. Solder wire connections between the motors and the
switches. Follow the schematic diagram for routing each
wire. Remember to use about 20 feet of wire for every
switch-to-motor connection. Two SPDT (single pole,
SERVO 05.2014 49
Wiring Schematic. Wiring connections for one directional control
motor (Y axis) for the Pool Bot propulsion system. Two SPDT
switches and one Tamiya submarine motor kit are used for each
directional control motor (i.e., Y axis, X axis, and Z axis).
Propulsion motor. The Y axis motor installed on Pool Bot.