Hey everyone!

I have an i3 clone that I built following the Thomas Sanladerer video series from years ago. I upgraded and moved on to other printers and such since then but now I am blowing the dust off of this one and making some upgrades. Specifically, I swapped from a RAMPS board to an SKR 1.4, started using Marlin 2.0, and upgraded the extruder housing to add the MK3S filament sensor.

The issue I am having is that the IR sensor does not seem to trigger correctly, or at all. Mechanically, everything is working as it should (the filament pushes the little ball that nudges the lever into the path of the beam, triggering the sensor). The problem is the sensor reads the same regardless of is there is filament loaded or not. Thinking it might be the sensor itself, I purchased a replacement and swapped it. Still no luck. I tested the Marlin config and wires by hooking up an old mechanical endstop switch and it reads as either triggered or open, accordingly.

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So, my issue is the IR sensor is not sending the appropriate signal when required. Does anyone have any suggestions?

Thanks for your help!