All software in source or binary form and Eagle-files on this site are under the FreeBSD-license.
To cite the project you can write:
Esben Rossel, (2017). The linear CCD module [Firmware]
You may of course use everything freely, but it makes me very happy to see the linear CCD in any kind of project, so I would very much appreciate a short message with a brief introduction of your project, if you use the material presented here.
Beware that the STM32 Nucleo F401RE is under ST’s evaluation license.