Filament sensor false positives (1 reply)

Hello Marlin forum

(my message got cut off here, retry)

I'm new (to this form that is) but I have quite a lot of experience with Marlin, 3D Printers in general, Ender 3, Ender 5 and Tenlog TL-D3 Pro in particular, so I will answer as many questions as I can.

At this time, however, I need some reflection; I have an Ender 3 (far from stock) with a runout sensor. The problem is the sensor triggers randomly.

I have changed the mainboard (was an SKR 1.4 Turbo, is now an SKR2), the sensor (was a simple switch, is now a BTT SFS), the cable, the firmware (2.0.x beta latest commit on feb 20).

Still randomly triggering the M600. What else can I do to fix this?

I've read that the FILAMENT_RUNOUT_DISTANCE_MM must be 7 mm for this sensor, and higher or lower will result in even more false positives. What options do I have? filament detection is -- effectively -- impossible at this time.

Thank you kindly for your input

my config (at least the relevant parts)

#define FILAMENT_RUNOUT_SENSOR
#if ENABLED(FILAMENT_RUNOUT_SENSOR)
  #define FIL_RUNOUT_ENABLED_DEFAULT true
  #define NUM_RUNOUT_SENSORS   1
  #define FIL_RUNOUT_STATE     HIGH
  #define FIL_RUNOUT_PULLUP
  //#define FIL_RUNOUT_PULLDOWN
  
  #define FILAMENT_RUNOUT_SCRIPT "M600"
  #define FILAMENT_RUNOUT_DISTANCE_MM 7
  #define FILAMENT_MOTION_SENSOR
#endif