Probe Tare, Probe Activation Switch (#20379)

Co-authored-by: Scott Lahteine <github@thinkyhead.com>
Co-authored-by: Victor Mateus Oliveira <rhapsodyv@gmail.com>
Co-authored-by: Jason Smith <jason.inet@gmail.com>

Marlin/Configuration.h

 #define Z_PROBE_SPEED_SLOW (Z_PROBE_SPEED_FAST / 2)
 
 /**
+ * Probe Activation Switch
+ * A switch indicating proper deployment, or an optical
+ * switch triggered when the carriage is near the bed.
+ */
+//#define PROBE_ACTIVATION_SWITCH
+#if ENABLED(PROBE_ACTIVATION_SWITCH)
+  #define PROBE_ACTIVATION_SWITCH_STATE LOW // State indicating probe is active
+  //#define PROBE_ACTIVATION_SWITCH_PIN PC6 // Override default pin
+#endif
+
+/**
+ * Tare Probe (determine zero-point) prior to each probe.
+ * Useful for a strain gauge or piezo sensor that needs to factor out
+ * elements such as cables pulling on the carriage.
+ */
+//#define PROBE_TARE
+#if ENABLED(PROBE_TARE)
+  #define PROBE_TARE_TIME  200    // (ms) Time to hold tare pin
+  #define PROBE_TARE_DELAY 200    // (ms) Delay after tare before
+  #define PROBE_TARE_STATE HIGH   // State to write pin for tare
+  //#define PROBE_TARE_PIN PA5    // Override default pin
+  #if ENABLED(PROBE_ACTIVATION_SWITCH)
+    //#define PROBE_TARE_ONLY_WHILE_INACTIVE  // Fail to tare/probe if PROBE_ACTIVATION_SWITCH is active
+  #endif
+#endif
+
+/**
  * Multiple Probing
  *
  * You may get improved results by probing 2 or more times.

Marlin/src/core/language.h

 #define STR_Z4_MIN                          "z4_min"
 #define STR_Z4_MAX                          "z4_max"
 #define STR_Z_PROBE                         "z_probe"
+#define STR_PROBE_EN                        "probe_en"
 #define STR_FILAMENT_RUNOUT_SENSOR          "filament"
 #define STR_PROBE_OFFSET                    "Probe Offset"
 #define STR_SKEW_MIN                        "min_skew_factor: "

Marlin/src/gcode/probe/M401_M402.cpp

  */
 void GcodeSuite::M401() {
   probe.deploy();
+  TERN_(PROBE_TARE, probe.tare());
   report_current_position();
 }
 

Marlin/src/inc/SanityCheck.h

     #error "Z_SAFE_HOMING is recommended when homing with a probe. Enable it or comment out this line to continue."
   #endif
 
+  #if ENABLED(PROBE_ACTIVATION_SWITCH)
+    #ifndef PROBE_ACTIVATION_SWITCH_STATE
+      #error "PROBE_ACTIVATION_SWITCH_STATE is required for PROBE_ACTIVATION_SWITCH."
+    #elif !PIN_EXISTS(PROBE_ACTIVATION_SWITCH)
+      #error "A PROBE_ACTIVATION_SWITCH_PIN is required for PROBE_ACTIVATION_SWITCH."
+    #endif
+  #endif
+
 #else
 
   /**

Marlin/src/module/endstops.cpp

     #endif
   #endif
 
+  #if ENABLED(PROBE_ACTIVATION_SWITCH)
+    SET_INPUT(PROBE_ACTIVATION_SWITCH_PIN);
+  #endif
+
+  TERN_(PROBE_TARE, probe.tare());
+
   TERN_(ENDSTOP_INTERRUPTS_FEATURE, setup_endstop_interrupts());
 
   // Enable endstops
   #if HAS_Z4_MAX
     ES_REPORT(Z4_MAX);
   #endif
+  #if BOTH(MARLIN_DEV_MODE, PROBE_ACTIVATION_SWITCH)
+    print_es_state(READ(PROBE_ACTIVATION_SWITCH_PIN) == PROBE_ACTIVATION_SWITCH_STATE, PSTR(STR_PROBE_EN));
+  #endif
   #if HAS_CUSTOM_PROBE_PIN
     print_es_state(PROBE_TRIGGERED(), PSTR(STR_Z_PROBE));
   #endif
     #endif
   #endif
 
-  #if HAS_Z_MIN && !Z_SPI_SENSORLESS
+  #if HAS_Z_MIN && NONE(Z_SPI_SENSORLESS, Z_MIN_PROBE_USES_Z_MIN_ENDSTOP_PIN)
     UPDATE_ENDSTOP_BIT(Z, MIN);
     #if ENABLED(Z_MULTI_ENDSTOPS)
       #if HAS_Z2_MIN
     #endif
   #endif
 
-  // When closing the gap check the enabled probe
-  #if HAS_CUSTOM_PROBE_PIN
-    UPDATE_ENDSTOP_BIT(Z, MIN_PROBE);
+  #if HAS_BED_PROBE
+    // When closing the gap check the enabled probe
+    if (true
+      #if ENABLED(PROBE_ACTIVATION_SWITCH)
+        || READ(PROBE_ACTIVATION_SWITCH_PIN) == PROBE_ACTIVATION_SWITCH_STATE
+      #endif
+    ) UPDATE_ENDSTOP_BIT(Z, TERN(HAS_CUSTOM_PROBE_PIN, MIN_PROBE, MIN));
   #endif
 
   #if HAS_Z_MAX && !Z_SPI_SENSORLESS

Marlin/src/module/motion.cpp

   // Fast move towards endstop until triggered
   if (DEBUGGING(LEVELING)) DEBUG_ECHOLNPGM("Home 1 Fast:");
 
-  #if BOTH(HOMING_Z_WITH_PROBE, BLTOUCH)
-    if (axis == Z_AXIS && bltouch.deploy()) return; // The initial DEPLOY
+  #if HOMING_Z_WITH_PROBE
+    if (axis == Z_AXIS) {
+      if (TERN0(BLTOUCH, bltouch.deploy())) return;
+      if (TERN0(PROBE_TARE, probe.tare())) return;
+    }
   #endif
 
   #if DISABLED(DELTA) && defined(SENSORLESS_BACKOFF_MM)

Marlin/src/module/probe.cpp

   return !probe_triggered;
 }
 
+#if ENABLED(PROBE_TARE)
+  /**
+   * @brief Tare the Z probe
+   *
+   * @details Signal to the probe to tare itself
+   *
+   * @return TRUE if the tare cold not be completed
+   */
+  bool Probe::tare() {
+    #if BOTH(PROBE_ACTIVATION_SWITCH, PROBE_TARE_ONLY_WHILE_INACTIVE)
+      if (READ(PROBE_ACTIVATION_SWITCH_PIN) == PROBE_ACTIVATION_SWITCH_STATE) {
+        SERIAL_ECHOLNPGM("Cannot tare an active probe");
+        return true;
+      }
+    #endif
+
+    SERIAL_ECHOLNPGM("Taring probe");
+    OUT_WRITE(PROBE_TARE_PIN, PROBE_TARE_STATE);
+    delay(PROBE_TARE_TIME);
+    OUT_WRITE(PROBE_TARE_PIN, !PROBE_TARE_STATE);
+    delay(PROBE_TARE_DELAY);
+
+    endstops.hit_on_purpose();
+    return false;
+  }
+#endif
+
 /**
  * @brief Probe at the current XY (possibly more than once) to find the bed Z.
  *
 float Probe::run_z_probe(const bool sanity_check/*=true*/) {
   DEBUG_SECTION(log_probe, "Probe::run_z_probe", DEBUGGING(LEVELING));
 
-  auto try_to_probe = [&](PGM_P const plbl, const float &z_probe_low_point, const feedRate_t fr_mm_s, const bool scheck, const float clearance) {
+  auto try_to_probe = [&](PGM_P const plbl, const float &z_probe_low_point, const feedRate_t fr_mm_s, const bool scheck, const float clearance) -> bool {
     // Do a first probe at the fast speed
+
+    if (TERN0(PROBE_TARE, tare())) return true;
+
     const bool probe_fail = probe_down_to_z(z_probe_low_point, fr_mm_s),            // No probe trigger?
                early_fail = (scheck && current_position.z > -offset.z + clearance); // Probe triggered too high?
     #if ENABLED(DEBUG_LEVELING_FEATURE)
   #if TOTAL_PROBING == 2
 
     // Do a first probe at the fast speed
+    if (TERN0(PROBE_TARE, tare())) return NAN;
+
     if (try_to_probe(PSTR("FAST"), z_probe_low_point, z_probe_fast_mm_s,
                      sanity_check, Z_CLEARANCE_BETWEEN_PROBES) ) return NAN;
 
     )
   #endif
     {
+      // If the probe won't tare, return
+      if (TERN0(PROBE_TARE, tare())) return true;
+
       // Probe downward slowly to find the bed
       if (try_to_probe(PSTR("SLOW"), z_probe_low_point, MMM_TO_MMS(Z_PROBE_SPEED_SLOW),
                        sanity_check, Z_CLEARANCE_MULTI_PROBE) ) return NAN;

Marlin/src/module/probe.h

     static void set_probing_paused(const bool p);
   #endif
 
+  #if ENABLED(PROBE_TARE)
+    static bool tare();
+  #endif
+
 private:
   static bool probe_down_to_z(const float z, const feedRate_t fr_mm_s);
   static void do_z_raise(const float z_raise);

buildroot/tests/STM32F103RET6_creality-tests

 exec_test $1 $2 "Ender 3 v2, SD EEPROM, w/o CLASSIC_JERK" "$3"
 
 restore_configs
+opt_set SERIAL_PORT 1
+opt_set MOTHERBOARD BOARD_CREALITY_V452
+opt_disable NOZZLE_TO_PROBE_OFFSET
+opt_enable NOZZLE_AS_PROBE Z_SAFE_HOMING Z_MIN_PROBE_USES_Z_MIN_ENDSTOP_PIN
+opt_enable PROBE_ACTIVATION_SWITCH PROBE_ACTIVATION_SWITCH_PIN PROBE_TARE PROBE_TARE_ONLY_WHILE_INACTIVE
+exec_test $1 $2 "Creality V4.5.2 PROBE_ACTIVATION_SWITCH, Probe Tare" "$3"
+
+# clean up
+restore_configs