Piezo underbed levelling (precisionpiezo)

Updated!

Today i changed piezo sensing to inductive proximity sensor with temperature control. for example PINDA v2 or any analogue sensor w. NTC. New marlin 2.0.9.3 supported temperature drift compensation and easy calibration. Solution is very very accurate allows measurement. external link:
https://zen3d.hu/p-i-n-d-a-marlin-konfiguracio/
https://www.youtube.com/watch?v=AjB0ZucPf9s

Sorry, this piezo project is abandoned, deprecated.






Piezo underbed project (Ender-3).

on working: https://www.twitch.tv/njozsef (if printing in progress)


update 2020-04-28
New balanced spring force (piezo disc pressure) adjusting screw to keep the piezo pressure within the piezo mechanical-limit in all surface. (replaced 27mm disc and ring holder to 20 mm discs + holder + pressure adjustment screw).
Thank you PeriniM https://www.thingiverse.com/thing:2137762
All new parts prefix 2020-04-28_partname.stl
measured deviation: 0.0031 !!!

after upgrade:
need settings "z-o