This project uses a prototype McRoboFace from 4Tronix. It is drven by a raspbery Pi and a 4Tronix Picon Zero board. An Audio feed to one of the built in A/D converters on the picon card is processed and used to control the neopixel leds that make up the face. The leds are controlled by the audio, and the mouth is triggered to open and close according to the amplitude of the signal. I have used it with an external micxrophone feed, and with Sonic Pi as the audio source. Full constructional details of the circuitry involved and the program development are available in an article at https://rbnrpi.wordpress.com/project-li ... -sonic-pi/ which also has download links to the software. A video in which the robot face explains itself how it works is available at https://youtu.be/bp6JeHgJFdY
4Tronix hope to run a Kickstarter project for the McRoboFace in the near future.