The capture device shown in Rescuing SW is a workprinter-16, which is described here: http://www.moviestuff.tv/wp_16.html
It looks like a projector because it was built out of a projector. But it doesn't project... the front side of the film is illuminated and the camera zooms in on it. It also has a different motor that controls both the advancement of the film and the clicking of the mouse to inform the computer to capture the frame.