Like when he needed shopping carts for a scene, he took his 10-year-old daughter to a grocery store, put the recorder in a cart, and they pretended to shop, banging into things in the parking lot.
He says sometimes he gets weird reactions from people when he does things to record sound, but in that case, he says having his 10-year-old with him was a good cover.
Burtt is also the voice of the main character, WALL-E.
The film is about a robot's journey of discovering his purpose in life. It opens today.
