The Ben Heck Show has a cool DIY Animatronic Puppet Head project. This project listens for speech and moves the puppet mouth accordingly.
 “In this episode Ben sets out to help Backflip films with their upcoming puppet movie The Princess Knight. The film requires its actors to memorize prerecorded dialogue in order to match it with the mouth of a puppet. In this episode Ben sets out to create an animatronic head that would move its mouth automatically by detecting the highs and lows of audio waveform.”