Nuts and Volts - September 2017

Hey! I’m Talkin’ Here!

The talking skull has been done to death (heh!), but seriously, what graveyard or spooky fall festival would be complete without a cowled crypt keeper entertaining the crowd with giggles and silly banter?

There are a ton of choices when it comes to talking skull setups. There are entry level skull systems that can be had for under $50 and then there are high-end commercial systems that start at $800 and go up from there. Or, if DIY is your style, the Internet is loaded with different self-serve skull systems.

So, what can we do different that will make our skull stand head and shoulders above the rest in power, performance, and features?

Introducing the Wee Little Talker

Talking skulls have come a long way since the original “Boris” units sold by Gemmy in the late 2000s (Figure 1).

These original skulls used a rather primitive system consisting of a small DC motor to wind up a string that, in turn, pulled open the jaw. To drive the motor, you spoke into a microphone that drove a small audio amplifier.

The output of the audio amplifier was then rectified and filtered to drive the motor to pull the jaw open until it reached a “stall” at the end of travel. When the audio level dropped, a spring would pull the jaw back to its default “closed” position and would pull the string back by unwinding it from the motor. This simplistic system provided fairly good audio/jaw sync as the amplitude of the audio created a proportional jaw movement. The next generation of talking skulls used RC receivers and servo motors to “puppet” the jaw. This allowed very precise control over jaw position, but it also required a relatively talented operator and quite a bit of rehearsal in order to put on a good performance (Figure 2). Another step forward came as folks noticed that servo motors lent themselves to programming via computer. With the addition of a serial servo control board, a computer, and some homebrew software (or $100 or more to purchase a commercial program!), you could record servo positions and synchronize them to sound files. This approach provided excellent results with pin-point accuracy for jaw sync, but it was VERY time intensive. Plus, once you had a show programmed, any change in the audio usually required you to re-program the entire sequence from scratch (Figure 3).