Kossel mini effector with probing nozzle and hall sensor.

thingiverse

This design is comparable to the effector being remixed I created earlier for a microswitch, but instead utilizing a small hall sensor module PCB. Specifically, I'm referring to this product from Sunfounder: https://www.sunfounder.com/modules/sensor-module/analog-hall-sensor-module.html. I employ it in analog mode with Duet firmware, however, I suspect it could also be used effectively with other firmwares in digital mode as well.