to include an onboard audio source.
His circuit was originally designed to be used when a
servo was added to a skull (Figure 3). This board has been
used extensively by those in the Halloween prop building
community with many different modifications made.
For my particular application, I first had to determine
the best position to mount the servo. The available space
was going to be tight — even using a mini servo (Figure 4).
In order to get the servo to fit in the correct orientation, I
had to remove the mounting tabs.
With the tabs removed, I now had to figure out a way
to securely attach the servo. I went with one of my favorite
methods: using Pro Poxy 20. This is a two-part epoxy that
comes in a tube and is easily combined into a workable
putty. You have several minutes to shape it as desired
before it hardens, and it provides a very solid connection.
You can sand, drill, and tap it once it’s cured, and it has a
myriad of uses for the prop builder.
Once this was complete, it was a simple matter to
connect the servo horn to the existing jaw mechanism. I
hooked it up to the controller board and reassembled the
monkey. He was quickly talking up a storm!
Let’s Get this Skull Moving!
This project utilizes the Lindberg Pirate Skull to which
the three-axis kit from Monster Guts is attached. It is
suggested that the Hitec 485BB servos be used, but the HS-
425BBs seem to work just fine. These kits are so well
balanced that the lighter torque servos have no problem
providing sufficient force to get great movement.
I've built several different designs to provide the nod,
tilt, and rotate motions to a skull, but have never quite
gotten the movement that I was after until this kit was
introduced. It has solved many of the issues from the other
designs and works like a champ!
Several modifications need to be made to the skull
before you install the actual three-axis mechanism. Using a
38 SERVO 08.2015
Figure 3. The head interior showing the available space.
Figure 4. Servo installed and attached to the linkage.
Figure 5. Skulls ready to speak using the Scary Terry design.