µManager is software for control of microscopes and runs as a plugin to ImageJ, is Open Source, and is free.
Information about installation: https://micro-manager.org/wiki/MatrixVision
Source code:
https://valelab4.ucsf.edu/svn/micromanager2/trunk/DeviceAdapters/MatrixVision/
https://valelab4.ucsf.edu/trac/micromanager/browser/DeviceAdapters/MatrixVision