she put together an optical audio decoder for old 16 mm film, built using modern components and a bit of 3D printing. It all started with a broken 16 mm projector that [Emily] got from a friend.

Do you know how a film projector works ... In [Bill]’s latest video, he tears down a 1979 Bell & Howell 16mm projector to probe its inner workings. Movies operate on the persistence of ...