Tachometer Fan Guide for Canbus users need diode

[waxall]

Was using your guide on the tach 3-pin hotend fan from Orion and noticed that Klipper wasn't reporting the RPM when attached to my Huvud CANBUS pcb when attached to 5V endstops. https://ellis3dp.com/Print-Tuning-Guide/articles/useful_macros/hotend_fan_monitoring.html

Managed to get it working when a Schotty Diode was added facing the fan side on the Signal line.

Attached is some documentation from the Voron discord I pulled that you might want to consider adding to that page so people don't fry their boards.

[reneas]

I should have read this earlier... I just fried my new SKR Mini E3 v3.0 board trying to set up the tachometer function... Basically sent 12V through the input pin and killed the microcontroller :( So if I put a diode facing towards the fan it should work as expected? Wouldn't the diode stop any signal from arriving at the tach input pin? I am not really super fit with electronics so it would be great if someone could explain this to me!