■ FIGURE 2. Cowlacious ST-200b version
of the audio servo board.
skulls and other animatronic heads. They have been
a very reliable addition to my haunt.”
The result was “Scary Terry’s Audio Servo Driver.”
This small board detects any incoming audio signal and
moves a servo motor to animate the jaw or mouth of
a prop. This way, no programming is needed and you
can change the sound track for the prop at any time.
Terry made the schematics, parts list, and proto
board circuit layouts available on his page (Figure 1)
and even published detailed information on the circuit
theory of operation. However, many folks found the
creation of the circuit a bit too complicated or time
consuming. Though the circuit was perfect for many
haunter’s needs, it really needed to be simplified and
documented (i.e., “kitted”) in order to make it more
accessible to less electronically advanced folks.
Cowlacious to the Rescue!
As an electronics technician by trade, Carl Cowley
(of Cowlacious Designs) was in the right place at the
right time to create a kit around Terry’s circuit. With
Terry’s permission and assistance, Carl took the original
schematic design and laid out a number of different
printed circuit board (PCB) revisions. He finally settled on the “ST-200b” version that was streamlined
and made more versatile (Figure 2). Though it is still quite
feasible to create the board based on the original prototype,
having a PCB silk-screened with component identifications,
a comprehensive instruction manual, and all the parts ready
to go makes things a LOT easier. Keeping in mind the
differing levels of experience of potential customers, the
kit is conveniently available assembled and tested if you
prefer not to build it yourself (Figure 3).
■ FIGURE 3. Cowlacious ST-200b fully assembled.
■ FIGURE 4.
September 2008 35