ESP8266 and OLED based monitor for Duet / RepRap based 3D printers - DanalEstes/DuetMonitor

Background
I was using an inductive sensor as my main Z_min sensor. I was unable to use it as bed leveling sensor because I was using a very thin and soft steel plate under the glass. This lead to several issues: the glass itself is not perfect. The steel plate under it was not flat even when compressed so both the steel and glass does not represent the REAL printing surface. Only a touching probe can give you that!!!
I like the idea of the piezo - but also plan to use PEI in the future and I would not like to touch a hot nozzle to that surface.
I like a lot the BLTouch - but the real thing is too expensive to my tastes and the clones are not that reliable and not so cheap as well.
I do not like the bulky thing, with movable wires and such, when using a servo and a mechanical end-stop. Also I do not trust the repeatability of the servo positioning.
I fall in love with these two designs:Robscar ThingJupacreations Thing
Cheap as heck, simple, reliable, no dependency on servo position (the servo just raise the probe…