What kind of sensors and other stuff do I need to achieve this?
Let's say those red and blue boxes are steel bars.
Red bar is fixed, blue bar slides up and down.
I need to attach a measurement to them so I know how much blue bar moves relative to the red bar.
I'm looking through industrial stuff on rs-online but I have no idea what do I need.
A rotary encoder would do the trick.
Like I told you on/g/, faggot, google for a linear motion encoder.
a laser mouse would work.
>>944510
As would a set of digital callipers. Which sounds like pretty much what he's trying to build.
>You're reinventing the wheel, OP.
>>944475
Capacitive linear encoder.
>>944514
This a pair of calipers rigged or a digital read out track.