Semi-automatic Bed Level Probe

This is a simple, micro-switch based bed level probe that costs less than $1 to make and gets the job done, reliably. Is is semi-automatic, in the sense that you attach it to the extruder or carriage, run the calibration routine (G29 in Marlin or G32 in Repetier) and then remove the probe. That means it does not add any weight to the print head, a nice plus for Delta or Bowden based printers. As long as you don't bump the printer or change the bed plate, the re-calibration is not needed.

It was designed to be quick-mount: it slides right on the effector plate on a Kossel (use the Customizer or OpenSCAD to adjust for other printers) and it takes only a few seconds to tighten for increased repeatability.

In terms of accuracy: I get a 20 micron repeatability but I can't say how much of that is because of the printer vs the probe vs the switch, the bottom line is all of those combined are less than 20 microns which is more than sufficient for most prints.

NOTE: If you are di