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AndrewEllis93 / Print-Tuning-Guide

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Tachometer Fan Guide for Canbus users need diode #97

Open waxall opened 9 months ago

waxall commented 9 months ago

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.

Screenshot_2022-12-19_at_12 38 51 Screenshot_2022-12-19_at_12 38 34

reneas commented 1 week ago

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!