Filament Motion Sensor on 2-in-1-out hotend?

General Discussion
5

Solved it, more or less.

[filament_motion_sensor] indeed expects a stepper, not an [extruder].

After adding

def find_past_position(self, print_time):
    return self.extruder_stepper.find_past_position(print_time)

to the PrinterExtruder class, I was able to set the following in my printer.cfg:

[filament_motion_sensor e0_sensor]
detection_length: 9
extruder: extruder
switch_pin: P1.26
pause_on_runout: False
runout_gcode: 
    RUNOUT_MACRO SOURCE=extruder

[filament_motion_sensor e1_sensor]
detection_length: 9
extruder: extruder_stepper extruder1
switch_pin: P1.25
pause_on_runout: False
runout_gcode:
    RUNOUT_MACRO SOURCE=extruder1

Now each filament_motion_sensor refers to its assigned stepper and ignores the movements of the other.

However, now both sensors triggered during toolchanges. I worked around this by setting pause_on_runout to False, using a custom runout macro and a delayed_gcode to ignore this during and immediately after toolchanges:

[gcode_macro RUNOUT_MACRO]
variable_toolchange: 0
gcode:
    {% set svv = printer.save_variables.variables %}
    {% if svv.currentextruder != params.SOURCE %}
        M118 IGNORING filament sensor { params.SOURCE } triggered while { svv.currentextruder } is active.
    {% elif toolchange == 1 %}
        M118 IGNORING filament sensor { params.SOURCE } triggered during toolchange.
    {% else %}
        M118 HALTING: Filament sensor { params.SOURCE } triggered.
        PAUSE_MACRO
    {% endif %}

[gcode_macro CHANGE_TOOLHEAD]
gcode:
    DISABLE_FILAMENT_SENSORS
    SWITCH_TOOL TARGET={ params.TARGET }
    UPDATE_DELAYED_GCODE ID=ENABLE_FILAMENT_SENSOR DURATION=10

[gcode_macro DISABLE_FILAMENT_SENSORS]
gcode:
    SET_GCODE_VARIABLE MACRO=RUNOUT_MACRO VARIABLE=toolchange VALUE=1

[delayed_gcode ENABLE_FILAMENT_SENSOR]
gcode:
  SET_GCODE_VARIABLE MACRO=RUNOUT_MACRO VARIABLE=toolchange VALUE=0

[gcode_macro SWITCH_TOOL]
gcode:
  M400
  SYNC_EXTRUDER_MOTION EXTRUDER="extruder" MOTION_QUEUE=""
  SYNC_EXTRUDER_MOTION EXTRUDER="extruder1" MOTION_QUEUE=""
  SYNC_EXTRUDER_MOTION EXTRUDER={ params.TARGET } MOTION_QUEUE="extruder"
  SAVE_VARIABLE VARIABLE=currentextruder VALUE='"{ params.TARGET }"'
  G92 E0

It’s not pretty, but it works.
Plus: This solution is independent from the ENABLE state of each sensor, meaning that I can toggle them from Mainsail at any time, without having my manual setting reset by the next toolchange.

If there aren’t any objections, I might submit a PR for my fix to the PrinterExtruder class.

1 Like
Filament_motion_sensor not working with extruder_stepper