FIGURE 8. The front and back of the robot is leveled using
skids. Adjust the length of the skids so that the robot will
slightly tip back and forth along its length.
• For the left mount assembly, the motor shaft should
face to the left, and toward the “top” of the deck (as
referenced in Figure 3). Attach the L brackets to the right
side of the mount.
• For the right mount assembly, the motor shaft should
face to the right, also toward the top of the deck. Attach
the L brackets to the left side of the mount.
Insert the machine screws through the L bracket, then
through the servo mount. Secure on the other end with a
nut. Before tightening, be sure the bottom of the L bracket
is flush with the bottom edge of the servo mount.
Attach the left mount assembly to the bottom deck
using 4-40 x 1/2” screws and nuts. The screws should come
up from the underside of the deck, through the L bracket
as shown in Figure 6. When orienting the mount assembly,
be sure that the servo shaft is centered in the wheel well
cut-out. Align the assembly so it is parallel with the wheel
well cut-out, then tighten all screws.
Repeat the same procedure for the right mount
assembly. Figure 7 shows how the completed servos and
mounts should look on the bottom deck of the robot.
Attach the front and rear skids as shown in Figure 8.
Each skid uses a 6-32” machine screw, hex nut, and acorn
1. Thread a machine screw into the hole at the front
and back base. The screw is inserted from the top of the
deck (the side with the servos).
2. Put the hex nut onto the screw, followed by the
acorn nut. Tighten the acorn nut against the hex nut.
Repeat these steps for the other skid.
You can adjust the height of the skid by loosening or
tightening the machine screw in the hole. If you need
FIGURE 9. Solder a 2.1 mm barrel connector to the nine volt
battery leads as shown. Be sure to double-check your work
against shorts, and that the red lead is soldered to the
center of the connector.
greater height adjustment or the hole for the skid is too
large to self-tap, merely use a longer machine screw, and
tighten into place using nuts on both the top and bottom
of the deck.
Important: Properly level the robot so there is only a
slight “teeter tot” forward and back. Otherwise, the bot
may not steer properly, and it could get caught up in even
the smallest of obstacles. If there’s too much teeter tot
movement, adjust the skids so they are closer in length to
one another. If there’s not enough movement, lengthen
Attach the wheels to the servos. Each wheel is secured
with a small self-tapping screw that is supplied with the
servo. Note that the servo shaft is splined, and this spline
matches the wheel hub. Be sure to press the wheel onto
SERVO 08.2013 45
FIGURE 10. Mount the nine volt battery to the bottom base
using a small piece of double-sided foam tape.