After some cases of vandalism (objects inserted in the lock from outside) I would like to get rid of this single point of failure by adding, on the internal side of the lock, an electro-mechanical mechanism to turn the lock from the inside. It would be powered by an Arduino. 

I know that there are electronic locks (the ones I saw had various issues) or anti-vandalism ones (no electronic parts) but I would like to try to roll out my own.

The problem I am having is that I could not find anywhere an insert which would be 

- normal on the outside part of the door (a classical hole for the key)
- hackable on the inside part of the door,

probably something like this

[![enter image description here][1]][1]

where I could attach something (a motor for instance) instead of the knob.

Do such inserts (cylinders) exist?



  [1]: https://i.sstatic.net/XphKh.png