YouTube has a number of excellent videos of restored Fotoplayers. The videos show how the sound effects modules were operated by little rope pulls suspended near the top of the instrument. I've embedded two clips below, but there are many more (search under "fotoplayer," "photoplayer" and "photo player").
The Fotoplayer was a mechanical theater piano with sound effects and organ attachments. It was made by American Photo Player (hence the confusion in spelling). This article on the Photoplayer from the Encyclopaedia of Australian Theatre Organs provides an excellent introduction to this general class of instrument as well as some additional photographs.
(H/T Julie Brown)
