Singing Sock Puppets

by Matthew Irvine Brown
http://www.irvinebrown.com/puppet.html

This is a singing sock puppet. There's a sensor inside that knows how wide his mouth is open, so he can sing up and down a scale. Open his mouth a little, he sings a low note; open wider, he sings a higher note; even wider, he screams at the top of his voice. And so on.