It is very convenient to have a more advanced measurement system than a Caliper to measure dimensions of various parts - maybe even make a cloud measurement / 3D scan. I found a very nice guide on construction from FABLab RUC. All credit goes to the inventors.
I just wanted to copy their design, and make my own digitizer. To try it myself using just an Arduino Mega. It is a simple and elegant concept, used in industrial digitizers also. Several inputs from encoders are used to calculate position of the point tip in real time. The software lets you store and plot data points - check out the guide, I link to it for more information
Digitizer in Action
My copy project of the digitizer in action