I showed my wife Tinkernut's Teddy Ruxpin youtube video (http://www.tinkernut.com/portfolio/alexa-ruxpin-raspberry-pi-alexa-teddy-bear/), and she had to order one. By the next day, she found ordered a "not functioning" teddy on ebay. My approach is different from others I had seen online, as I can drive servo motors with the Raspberry Pi, and not needing an arduino. One analog stick controls the mouth, the other controls the eyes. Movement is proportional to the deflection of the joysticks.