Dockable omnidirectional kinematic touch probe

thingiverse

Operation: https://youtu.be/cklbMCITKlg Working principle: same as touch CNC probes. The probe is fully 6-DOF constrained by 6 points of contact (both electrical and mechanical) that are wired in series. The probe can't move or tilt in any direction without breaking at least one of contacts. Further reading: https://en.wikipedia.org/wiki/Kinematic_coupling Note that the magnets on the probe and the base must not touch one another, the probe should be resting only on the wires. The base accepts one or two magnets, for lesser or greater preload on the contacts. BOM: 0.3..0.5 mm^2 (20 or 22 AWG) solid core wire, 2x or 3x 5mm diameter 1mm thick disk magnets (3x for stiffer attachment), m2 screw, length to taste. Some superglue (for magnets). Wiring guide, assembly: TODO. Note: the wires in the probe base should go between the top of the "canyon" and the furthermost(!) hole in the bottom of the "canyon". All of the points of contact should be electrically in series. After installing the wires it's best to melt them into the print with a soldering iron, to make sure they can't move and ruin repeatability. If using the dock, 2x m4x8 screws and T-nuts or other rail mounting hardware. Typical m48 standard deviation on my machine: <2 micrometers, regardless of whether the probe was docked between the probings or not. The source code is in https://github.com/Dmytry/Pythagoras/blob/main/mechanics/build123d_test/kinematic_probe.py The assembly is not precision critical; what you need is that the probe reliably seats into the contacts. Since there are no extraneous constraints, it will always self align in the same way provided that you don't have any extra points of contact beyond wires touching one another.