HyperCube Evolution: Ultra-Compact optical endstop for Z axis

Project files and photos
For some reason, the Thingiverse service does not show preview for photos attached to the project. For three days I tried to format the images in different ways - but to no avail.
All project files are available for download on the “Thing Files” tab.
Photos are added on this page below.

Design description
The solution is very simple, very reliable, very compact and very convenient - such a sensor does not interfere with any kind of work. The sensor is mounted on t