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
+// The number of probes to perform at each point.
-//#define PROBE_DOUBLE_TOUCH
+//   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/src/gcode/probe/G38.cpp

@@ -35,7 +35,7 @@ static bool G38_run_probe() {
 
   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) {
@@ -62,7 +62,7 @@ static bool G38_run_probe() {
 
     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/src/inc/SanityCheck.h

@@ -227,6 +227,8 @@
   #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
 
 /**
@@ -711,6 +713,10 @@ 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
 
   /**

Marlin/src/module/probe.cpp

@@ -507,7 +507,7 @@ static bool do_probe_move(const float z, const float fr_mm_m) {
 }
 
 /**
- * @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
@@ -521,7 +521,8 @@ static float run_z_probe() {
   // Prevent stepper_inactive_time from running out and EXTRUDER_RUNOUT_PREVENT from extruding
   gcode.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;
@@ -549,22 +550,49 @@ static float run_z_probe() {
     }
   #endif
 
-  // Move down slowly to find bed, not too far
+  #if MULTIPLE_PROBING > 2
-  if (do_probe_move(-10, Z_PROBE_SPEED_SLOW)) return NAN;
+    float probes_total = 0;
+    for (uint8_t p = MULTIPLE_PROBING + 1; --p;) {
+  #endif
+
+      // Move down slowly to find bed, not too far
+      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
+
+  #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
-
-  // 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]);
-    }
-  #endif
-
-  return current_position[Z_AXIS];
 }
 
 /**