gPhoto is a program and library framework that lets users download pictures from their digital cameras. The libgphoto2 library gives you access to hundreds of models of digital cameras on several platforms.
GIT repo and Issue tracker lives at https://github.com/gphoto/ these days.
Driver for the Polhemus Liberty v2 (tm) motion tracker.
Driver programmed in C, using libUSB. Outputs position and orientation data for all detected sensors. Easy to modify and include in your own programs.