Linear Stop

I am interested in making a Linear Stop using Openbuilds
something similar to this
http://rexelpoland.com/en/catalog/view/9/3/manual-length-measuring-stop-pr-1

I would like to be able to Set a Distance and have it move to that position. but also be able to move it manually by hand if needed and have it report back the current length.

Any advise regarding getting a arduino or other controller to do this would be appreciated.