Add support to duet laser filament sensor

README.md

@@ -92,6 +92,7 @@ Used IO pin headers
 * io_0 - display
 * io_1 - y endstop
 * io_2 - x endstop
+* io_3 - Duet filament sensor
 * io_7 - bltouch
 
 #### Stepper motors
@@ -124,7 +125,6 @@ Thermal probes in use:
 * temp1 - Hotend thermistor
 
 ## TODO
-- Setup filament sensor
 - Add printing tracking camera 
 
 - All macros are untested until stated otherwise (some are cloned from duet repos, others are mine), list of tested macros: 

config.g

@@ -78,6 +78,10 @@ G10 P0 R0 S0                                       ; set initial tool 0 active a
 
 ; Custom settings are not defined
 
+; Filament sensor - Duet3D laser filament monitor
+M574 E0 S1 P"io4.in"                               ; configure extruder endstop 
+M591 D0 P5 C"e0_stop" R40:120 E3.0 S0              ; Duet3D laser sensor for extruder drive 0, connected to endstop input 3 (E0), tolerance 40 to 120%, 3mm comparison length, disabled
+
 ; Miscellaneous
 M575 P1 S1 B57600                                  ; enable support for PanelDue
 M501                                               ; load saved parameters from non-volatile memory
@@ -85,3 +89,4 @@ M911 S10 R11 P"M913 X0 Y0 G91 M83 G1 Z3 E-5 F1000" ; set tension thresholds and
 M404 N1.75 D0.4                                    ; Filament width and nozzle diameter
 M572 D0 S0.10  	                                   ; Pressure Advance
 T0                                                 ; Define default tool
+G29 S1						   ; Load saved height map