My bold plans to add a multitude of animatronic
figures for my display quickly convinced me that unless I
won the lottery, I was going to have to reconsider my
strategy! This challenged me to learn to design and
produce my own controllers. In this way, I was able to put
together a PCB to fit any need I might dream up without
having to rely on currently available models. My cost was
paid in time and the required effort to learn how to
properly accomplish this. In return, I am able to put
together a controller that fits my needs perfectly and does
not break my budget.
One of my first forays into building my own controllers
was to design a two-channel button banger (see Figure 4).
If you are not familiar with this type of controller, it only
requires you to push the programming buttons to activate
the relays in your desired sequence. The actual
programming is already installed on the chip and the end
user never needs to worry about it. Even though the
available units on the market were well put together and
came encased in a sturdy enclosure, they were not cheap.
The other drawback that truly annoyed me was the poor
audio quality as it was in mono. I am sure the manufacturer
felt like that was sufficient, but I certainly did not. I wanted
higher quality stereo sound!
The availability of several low cost audio boards allowed
for the inclusion of stereo sound at an extremely reasonable
price (Figure 5). For less than $10, an audio module can be
attached to our designs that accept an SD card with our
sound files. There are several models available that have
already been tested and their idiosyncrasies discovered (see
My design was modified by fellow builder, Tyler Straub
with his version being a dramatic improvement over mine.
His most current version provides four relay outputs, has
reverse polarity protection, and incorporates a very handy
extension board for programming (see Figure 6).
This board is now affectionately referred to as the
Scuba Board after Tim Thompson who has enthusiastically
promoted and sold the board for Tyler. He has put together
some thorough videos detailing the operation and making
it easy for even a beginner to set up. You can check it out
along with the evolution of the design on the forum thread
which is included with the Resources.
The development of the button banger design allowed
those builders without any programming experience to
quickly and easily lay down a prop activation sequence. This
is a great solution for someone just getting started in
animating their own characters. If the DIY solution is not
for you, some of the most popular commercially made
models are supplied by FrightProps — the makers of the
PicoVolt discussed earlier — and are very dependable.
Another shortcoming of the available controllers that
bothered me was the complexity of controlling a three-axis
talking skull. I have included this feature on many of my
characters, and it required significant time and effort to
individually program every movement on each servo. Many
of the settings where our characters are placed do not
require programmed and set movements. Random
movement of the head servos is more than sufficient, yet
nothing suitable was available to do this. With the help of
several online building buddies, I was able to put together
the Frankenstein board that provided random head
movement, could be triggered, and included an onboard
audio player which could be synced up with the jaw. This
allowed the jaw to respond to an audio track in a realistic
manner (Figure 7).
As is true with most things, my initial design left plenty
of room for improvement. Upon sharing my design with
Steve Bjork, a fellow haunter and programmer, we came up
with several improvements. With Steve’s assistance, an
audio prompt system was added to facilitate the board
SERVO 08.2016 49
Figure 8. The three-axis controller continues to evolve.
Figure 7. The initial version of my three-axis controller.