Saturday, October 13, 2012

Toy's mouth motion by servo

Build Your Own Mouth Animation

Monstrous creatures are more convincing if they do something, like move or talk. Talking monsters make your haunt a graveyard smash, but how do you do it? In 2002, it became difficult to find pre-assembled talking gadgets that could be modified for Halloween use. Suddenly, it became more practical - and important - to be able to build your own from scratch.
This page surveys ways to build your own device that takes an audio stream and moves a mouth mechanism to match.

  • RC Servos
    • Ray Martin servo
    • Scary Terry servo
    • Wale and Noon servo
    • Derek Verner servo
  • Solenoids
    • Noon solenoid
  • DC Motors
    • Jim Kadel toy servo
  • Related Pages

RC Servos

RC servo for animated creature mouths...

Ray Martin servo

Ray Martin is a friend of ours who designs toys for a living, sometimes electronic, sometimes mechanical. We were having lunch after the TRW Amateur Radio Club swap meet, and I mentioned that some of the best
hackable products with animated mouths were discontinued, and Halloween lovers were constructing alternatives out of things like servos. Ray said, "I have a circuit that does exactly what you need on my desk right now!" Ray went further than that. He customized it for specific servo limits and pulse frequency, built and tested it, and sent it to me.
Click for full size schematic.

We have a page dedicated to details of Ray's Sound-To-Servo Driver.


Scary Terry servo

I believe that Scary Terry is the grandfather of made-from-scratch talking creatures. When he noticed that Douglas Fir and other hackable animated figures were disappearing from the stores, Terry forged ahead and built his own.
Terry's design uses a RC servo embedded in a plastic skull.

Click for full size schematic. This is rev 3.1 of his design, dated 8/20/2002.

For more hauntingly clever ideas, visit Scary Terry's web site at


Wale and Noon servo

The November 2002 (Vol 23, no 11) issue of Nuts and Volts contains an article by John Wale and Walt Noon (pg 72-76).
The article describes an animated Christmas train that carries talking gift boxes. The talking boxes use a RC servo for the mouth motion.
Click for full size schematic.
The transformer is 8-ohm to 1K. Presumably the 8-ohm side goes to the audio input, and the 1K side goes to the transistor that controls the 555 timer.


Derek Verner servo

Wolfstone reader Derek Verner wrote in July 2005 to describe his sound-to-servo solution. Here's how Derek described it:
Velleman makes a four servo controller that uses as its inputs voltages from zero to five volts. ... I use speaker level output from the recorders to drive small lamps that form part of opto-isolators. The other halves are CDS photocells. Each CDS cell is fed to an input of the controller in series with a trimmer pot. Across the pot (from one end to the wiper) is a voltage of six volts. When the recorded sound output is higher the lamp glows brighter and a higher voltage is fed to the controller. One need only vary the volume of the sound while recording to control the servo position.
Actually, there's a typo in there. Derek meant DIY Electronics, Kit 102 - Servo Motor Driver.


solenoids for animated creature mouths...

Noon solenoid

The September 2002 issue of Nuts and Volts contains an article by Walt Noon (pg 46) describing some of his haunt props, a pneumatic popup and a talking seagull. Included was a schematic for a mouth circuit that uses a solenoid to actuate the jaw.
Click for full size schematic.

Walt offers more information at his web site at


DC Motors

electric motors for animated creature mouths...

Jim Kadel toy servo

Jim Kadel, who runs
Haunt Master Products, Inc. also has a web site for his home haunt, where he generously provides technical information on some of his noncommercial projects. For Halloween 2003, Jim presented a schematic to retrofit talking props that use small DC motors as servos.
Click for full size schematic.

For more information, please visit Jim's web site at


No comments: