PROBE_DOUBLE_TOUCH => MULTIPLE_PROBING

Marlin/Configuration.h

@@ -690,14 +690,16 @@
 // X and Y axis travel speed (mm/m) between probes
 #define XY_PROBE_SPEED 8000
 
-// Speed for the first approach when double-probing (with PROBE_DOUBLE_TOUCH)
+// Speed for the first approach when double-probing (MULTIPLE_PROBING == 2)
 #define Z_PROBE_SPEED_FAST HOMING_FEEDRATE_Z
 
 // Speed for the "accurate" probe of each point
 #define Z_PROBE_SPEED_SLOW (Z_PROBE_SPEED_FAST / 2)
 
-// Use double touch for probing
-//#define PROBE_DOUBLE_TOUCH
+// The number of probes to perform at each point.
+//   Set to 2 for a fast/slow probe, using the second probe result.
+//   Set to 3 or more for slow probes, averaging the results.
+//#define MULTIPLE_PROBING 2
 
 /**
  * Z probes require clearance when deploying, stowing, and moving between

Marlin/Configuration_adv.h

@@ -742,7 +742,7 @@
 //#define BEZIER_CURVE_SUPPORT
 
 // G38.2 and G38.3 Probe Target
-// Enable PROBE_DOUBLE_TOUCH if you want G38 to double touch
+// Set MULTIPLE_PROBING if you want G38 to double touch
 //#define G38_PROBE_TARGET
 #if ENABLED(G38_PROBE_TARGET)
   #define G38_MINIMUM_MOVE 0.0275 // minimum distance in mm that will produce a move (determined using the print statement in check_move)

Marlin/Marlin_main.cpp

@@ -2215,7 +2215,7 @@ static void clean_up_after_endstop_or_probe_move() {
   }
 
   /**
-   * @details Used by probe_pt to do a single Z probe.
+   * @details Used by probe_pt to do a single Z probe at the current position.
    *          Leaves current_position[Z_AXIS] at the height where the probe triggered.
    *
    * @return The raw Z position where the probe was triggered
@@ -2229,7 +2229,8 @@ static void clean_up_after_endstop_or_probe_move() {
     // Prevent stepper_inactive_time from running out and EXTRUDER_RUNOUT_PREVENT from extruding
     refresh_cmd_timeout();
 
-    #if ENABLED(PROBE_DOUBLE_TOUCH)
+    // Double-probing does a fast probe followed by a slow probe
+    #if MULTIPLE_PROBING == 2
 
       // Do a first probe at the fast speed
       if (do_probe_move(-10, Z_PROBE_SPEED_FAST)) return NAN;
@@ -2257,22 +2258,49 @@ static void clean_up_after_endstop_or_probe_move() {
       }
     #endif
 
-    // move down slowly to find bed
-    if (do_probe_move(-10, Z_PROBE_SPEED_SLOW)) return NAN;
-
-    #if ENABLED(DEBUG_LEVELING_FEATURE)
-      if (DEBUGGING(LEVELING)) DEBUG_POS("<<< run_z_probe", current_position);
+    #if MULTIPLE_PROBING > 2
+      float probes_total = 0;
+      for (uint8_t p = MULTIPLE_PROBING + 1; --p;) {
     #endif
 
-    // Debug: compare probe heights
-    #if ENABLED(PROBE_DOUBLE_TOUCH) && ENABLED(DEBUG_LEVELING_FEATURE)
-      if (DEBUGGING(LEVELING)) {
-        SERIAL_ECHOPAIR("2nd Probe Z:", current_position[Z_AXIS]);
-        SERIAL_ECHOLNPAIR(" Discrepancy:", first_probe_z - current_position[Z_AXIS]);
+        // move down slowly to find bed
+        if (do_probe_move(-10, Z_PROBE_SPEED_SLOW)) return NAN;
+
+    #if MULTIPLE_PROBING > 2
+        probes_total += current_position[Z_AXIS];
+        if (p > 1) do_blocking_move_to_z(current_position[Z_AXIS] + Z_CLEARANCE_BETWEEN_PROBES, MMM_TO_MMS(Z_PROBE_SPEED_FAST));
       }
     #endif
 
-    return current_position[Z_AXIS];
+    #if MULTIPLE_PROBING > 2
+
+      // Return the average value of all probes
+      return probes_total * (1.0 / (MULTIPLE_PROBING));
+
+    #elif MULTIPLE_PROBING == 2
+
+      const float z2 = current_position[Z_AXIS];
+
+      #if ENABLED(DEBUG_LEVELING_FEATURE)
+        if (DEBUGGING(LEVELING)) {
+          SERIAL_ECHOPAIR("2nd Probe Z:", z2);
+          SERIAL_ECHOLNPAIR(" Discrepancy:", first_probe_z - z2);
+        }
+      #endif
+
+      // Return a weighted average of the fast and slow probes
+      return (z2 * 3.0 + first_probe_z * 2.0) * 0.2;
+
+    #else
+
+      // Return the single probe result
+      return current_position[Z_AXIS];
+
+    #endif
+
+    #if ENABLED(DEBUG_LEVELING_FEATURE)
+      if (DEBUGGING(LEVELING)) DEBUG_POS("<<< run_z_probe", current_position);
+    #endif
   }
 
   /**
@@ -6005,7 +6033,7 @@ void home_all_axes() { gcode_G28(true); }
 
     bool G38_pass_fail = false;
 
-    #if ENABLED(PROBE_DOUBLE_TOUCH)
+    #if MULTIPLE_PROBING > 1
       // Get direction of move and retract
       float retract_mm[XYZ];
       LOOP_XYZ(i) {
@@ -6032,7 +6060,7 @@ void home_all_axes() { gcode_G28(true); }
 
       G38_pass_fail = true;
 
-      #if ENABLED(PROBE_DOUBLE_TOUCH)
+      #if MULTIPLE_PROBING > 1
         // Move away by the retract distance
         set_destination_from_current();
         LOOP_XYZ(i) destination[i] += retract_mm[i];

Marlin/SanityCheck.h

@@ -224,6 +224,8 @@
   #error "UBL_GRANULAR_SEGMENTATION_FOR_CARTESIAN is now SEGMENT_LEVELED_MOVES. Please update your configuration."
 #elif HAS_PID_HEATING && (defined(K1) || !defined(PID_K1))
   #error "K1 is now PID_K1. Please update your configuration."
+#elif defined(PROBE_DOUBLE_TOUCH)
+  #error "PROBE_DOUBLE_TOUCH is now MULTIPLE_PROBING. Please update your configuration."
 #endif
 
 /**
@@ -698,6 +700,10 @@ static_assert(1 >= 0
     #error "Probes need Z_CLEARANCE_BETWEEN_PROBES >= 0."
   #endif
 
+  #if MULTIPLE_PROBING && MULTIPLE_PROBING < 2
+    #error "MULTIPLE_PROBING must be >= 2."
+  #endif
+
 #else
 
   /**