Thanks for the reply,
The design could use a linear or rotary encoder no problem. My first problem was sorting out if it's possible and why kit to use. If the linear encoder is easiest then that will be the option. How I'm going to get the signal into the pc is now the issue. I did wonder I I could get a ready made module that converted the signal to USB or com port? How would this be done in industry? Would the signal go straight into a PLC?

Cheers,
Ant