Add Chamber servo vent, auto fan (#19519)

Marlin/Configuration_adv.h

  */
 #define CONFIGURATION_ADV_H_VERSION 020007
 
-// @section temperature
-
 //===========================================================================
 //============================= Thermal Settings ============================
 //===========================================================================
+// @section temperature
 
 /**
  * Thermocouple sensors are quite sensitive to noise.  Any noise induced in
   #define HEATER_BED_INVERTING true
 #endif
 
-/**
- * Heated Chamber settings
- */
+//
+// Heated Bed Bang-Bang options
+//
+#if DISABLED(PIDTEMPBED)
+  #define BED_CHECK_INTERVAL 5000   // (ms) Interval between checks in bang-bang control
+  #if ENABLED(BED_LIMIT_SWITCHING)
+    #define BED_HYSTERESIS 2        // (°C) Only set the relevant heater state when ABS(T-target) > BED_HYSTERESIS
+  #endif
+#endif
+
+//
+// Heated Chamber options
+//
 #if TEMP_SENSOR_CHAMBER
   #define CHAMBER_MINTEMP             5
   #define CHAMBER_MAXTEMP            60
   //#define CHAMBER_LIMIT_SWITCHING
   //#define HEATER_CHAMBER_PIN       44   // Chamber heater on/off pin
   //#define HEATER_CHAMBER_INVERTING false
-#endif
 
-#if DISABLED(PIDTEMPBED)
-  #define BED_CHECK_INTERVAL 5000 // ms between checks in bang-bang control
-  #if ENABLED(BED_LIMIT_SWITCHING)
-    #define BED_HYSTERESIS 2 // Only disable heating if T>target+BED_HYSTERESIS and enable heating if T>target-BED_HYSTERESIS
+  //#define CHAMBER_FAN               // Enable a fan on the chamber
+  #if ENABLED(CHAMBER_FAN)
+    #define CHAMBER_FAN_MODE 2        // Fan control mode: 0=Static; 1=Linear increase when temp is higher than target; 2=V-shaped curve.
+    #if CHAMBER_FAN_MODE == 0
+      #define CHAMBER_FAN_BASE  255   // Chamber fan PWM (0-255)
+    #elif CHAMBER_FAN_MODE == 1
+      #define CHAMBER_FAN_BASE  128   // Base chamber fan PWM (0-255); turns on when chamber temperature is above the target
+      #define CHAMBER_FAN_FACTOR 25   // PWM increase per °C above target
+    #elif CHAMBER_FAN_MODE == 2
+      #define CHAMBER_FAN_BASE  128   // Minimum chamber fan PWM (0-255)
+      #define CHAMBER_FAN_FACTOR 25   // PWM increase per °C difference from target
+    #endif
+  #endif
+
+  //#define CHAMBER_VENT              // Enable a servo-controlled vent on the chamber
+  #if ENABLED(CHAMBER_VENT)
+    #define CHAMBER_VENT_SERVO_NR  1  // Index of the vent servo
+    #define HIGH_EXCESS_HEAT_LIMIT 5  // How much above target temp to consider there is excess heat in the chamber
+    #define LOW_EXCESS_HEAT_LIMIT 3
+    #define MIN_COOLING_SLOPE_TIME_CHAMBER_VENT 20
+    #define MIN_COOLING_SLOPE_DEG_CHAMBER_VENT 1.5
   #endif
 #endif
 

Marlin/src/inc/Conditionals_LCD.h

   #define DO_SWITCH_EXTRUDER 1
 #endif
 
-#ifdef SWITCHING_NOZZLE_E1_SERVO_NR
-  #define SWITCHING_NOZZLE_TWO_SERVOS 1
-#endif
-
 /**
  * Default hotend offsets, if not defined
  */
   #ifndef Z_PROBE_SERVO_NR
     #define Z_PROBE_SERVO_NR 0
   #endif
-  #ifndef NUM_SERVOS
-    #define NUM_SERVOS (Z_PROBE_SERVO_NR + 1)
-  #endif
   #undef DEACTIVATE_SERVOS_AFTER_MOVE
-  #if NUM_SERVOS == 1
-    #undef SERVO_DELAY
-    #define SERVO_DELAY { 50 }
-  #endif
 
   // Always disable probe pin inverting for BLTouch
   #undef Z_MIN_PROBE_ENDSTOP_INVERTING
   #endif
 #endif
 
-#ifndef NUM_SERVOS
-  #define NUM_SERVOS 0
-#endif
-
 /**
  * Set a flag for a servo probe (or BLTouch)
  */
-#if defined(Z_PROBE_SERVO_NR) && Z_PROBE_SERVO_NR >= 0
+#ifdef Z_PROBE_SERVO_NR
   #define HAS_Z_SERVO_PROBE 1
 #endif
 #if ANY(HAS_Z_SERVO_PROBE, SWITCHING_EXTRUDER, SWITCHING_NOZZLE)

Marlin/src/inc/Conditionals_adv.h

  * Defines that depend on advanced configuration.
  */
 
+#ifdef SWITCHING_NOZZLE_E1_SERVO_NR
+  #define SWITCHING_NOZZLE_TWO_SERVOS 1
+#endif
+
+// Determine NUM_SERVOS if none was supplied
+#ifndef NUM_SERVOS
+  #define NUM_SERVOS 0
+  #if ANY(CHAMBER_VENT, HAS_Z_SERVO_PROBE, SWITCHING_EXTRUDER, SWITCHING_NOZZLE)
+    #if NUM_SERVOS <= Z_PROBE_SERVO_NR
+      #undef NUM_SERVOS
+      #define NUM_SERVOS (Z_PROBE_SERVO_NR + 1)
+    #endif
+    #if NUM_SERVOS <= CHAMBER_VENT_SERVO_NR
+      #undef NUM_SERVOS
+      #define NUM_SERVOS (CHAMBER_VENT_SERVO_NR + 1)
+    #endif
+    #if NUM_SERVOS <= SWITCHING_TOOLHEAD_SERVO_NR
+      #undef NUM_SERVOS
+      #define NUM_SERVOS (SWITCHING_TOOLHEAD_SERVO_NR + 1)
+    #endif
+    #if NUM_SERVOS <= SWITCHING_NOZZLE_SERVO_NR
+      #undef NUM_SERVOS
+      #define NUM_SERVOS (SWITCHING_NOZZLE_SERVO_NR + 1)
+    #endif
+    #if NUM_SERVOS <= SWITCHING_NOZZLE_E1_SERVO_NR
+      #undef NUM_SERVOS
+      #define NUM_SERVOS (SWITCHING_NOZZLE_E1_SERVO_NR + 1)
+    #endif
+    #if NUM_SERVOS <= SWITCHING_EXTRUDER_SERVO_NR
+      #undef NUM_SERVOS
+      #define NUM_SERVOS (SWITCHING_EXTRUDER_SERVO_NR + 1)
+    #endif
+    #if NUM_SERVOS <= SWITCHING_EXTRUDER_E23_SERVO_NR
+      #undef NUM_SERVOS
+      #define NUM_SERVOS (SWITCHING_EXTRUDER_E23_SERVO_NR + 1)
+    #endif
+  #endif
+#endif
+
+// Convenience override for a BLTouch alone
+#if ENABLED(BLTOUCH) && NUM_SERVOS == 1
+  #undef SERVO_DELAY
+  #define SERVO_DELAY { 50 }
+#endif
+
 #if EXTRUDERS == 0
   #define NO_VOLUMETRICS
   #undef TEMP_SENSOR_0

Marlin/src/inc/SanityCheck.h

    * NUM_SERVOS is required for a Z servo probe
    */
   #if HAS_Z_SERVO_PROBE
-    #ifndef NUM_SERVOS
-      #error "You must set NUM_SERVOS for a Z servo probe (Z_PROBE_SERVO_NR)."
+    #if !NUM_SERVOS
+      #error "NUM_SERVOS is required for a Z servo probe (Z_PROBE_SERVO_NR)."
+    #elif Z_PROBE_SERVO_NR >= NUM_SERVOS
+      #error "Z_PROBE_SERVO_NR must be smaller than NUM_SERVOS."
     #elif Z_PROBE_SERVO_NR == 0 && !PIN_EXISTS(SERVO0)
       #error "SERVO0_PIN must be defined for your servo or BLTOUCH probe."
     #elif Z_PROBE_SERVO_NR == 1 && !PIN_EXISTS(SERVO1)
       #error "SERVO2_PIN must be defined for your servo or BLTOUCH probe."
     #elif Z_PROBE_SERVO_NR == 3 && !PIN_EXISTS(SERVO3)
       #error "SERVO3_PIN must be defined for your servo or BLTOUCH probe."
-    #elif Z_PROBE_SERVO_NR >= NUM_SERVOS
-      #error "Z_PROBE_SERVO_NR must be smaller than NUM_SERVOS."
     #endif
   #endif
 
   #error "TEMP_SENSOR_CHAMBER requires TEMP_CHAMBER_PIN. Please add it to your configuration."
 #endif
 
+#if ENABLED(CHAMBER_FAN) && !(defined(CHAMBER_FAN_MODE) && WITHIN(CHAMBER_FAN_MODE, 0, 2))
+  #error "CHAMBER_FAN_MODE must be between 0 and 2. Please update your Configuration_adv.h."
+#endif
+
+#if ENABLED(CHAMBER_VENT)
+  #ifndef CHAMBER_VENT_SERVO_NR
+    #error "CHAMBER_VENT_SERVO_NR is required for CHAMBER SERVO. Update your Configuration_adv.h."
+  #elif !NUM_SERVOS
+    #error "NUM_SERVOS is required for a Heated Chamber vent servo (CHAMBER_VENT_SERVO_NR)."
+  #elif CHAMBER_VENT_SERVO_NR >= NUM_SERVOS
+    #error "CHAMBER_VENT_SERVO_NR must be smaller than NUM_SERVOS."
+  #elif HAS_Z_SERVO_PROBE && CHAMBER_VENT_SERVO_NR == Z_PROBE_SERVO_NR
+    #error "CHAMBER SERVO is already used by BLTOUCH. Please change."
+  #elif CHAMBER_VENT_SERVO_NR == 0 && !PIN_EXISTS(SERVO0)
+    #error "SERVO0_PIN must be defined for your Heated Chamber vent servo."
+  #elif CHAMBER_VENT_SERVO_NR == 1 && !PIN_EXISTS(SERVO1)
+    #error "SERVO1_PIN must be defined for your Heated Chamber vent servo."
+  #elif CHAMBER_VENT_SERVO_NR == 2 && !PIN_EXISTS(SERVO2)
+    #error "SERVO2_PIN must be defined for your Heated Chamber vent servo."
+  #elif CHAMBER_VENT_SERVO_NR == 3 && !PIN_EXISTS(SERVO3)
+    #error "SERVO3_PIN must be defined for your Heated Chamber vent servo."
+  #endif
+#endif
+
 #if TEMP_SENSOR_PROBE
   #if !PIN_EXISTS(TEMP_PROBE)
     #error "TEMP_SENSOR_PROBE requires TEMP_PROBE_PIN. Please add it to your configuration."

Marlin/src/module/temperature.cpp

   #include "../libs/buzzer.h"
 #endif
 
+#if HAS_SERVOS
+  #include "./servo.h"
+#endif
 #if HOTEND_USES_THERMISTOR
   #if ENABLED(TEMP_SENSOR_1_AS_REDUNDANT)
     static const temp_entry_t* heater_ttbl_map[2] = { HEATER_0_TEMPTABLE, HEATER_1_TEMPTABLE };
 #if HAS_TEMP_CHAMBER
   chamber_info_t Temperature::temp_chamber; // = { 0 }
   #if HAS_HEATED_CHAMBER
+    int16_t fan_chamber_pwm;
+    bool flag_chamber_off;
+    bool flag_chamber_excess_heat = false;
+    millis_t next_cool_check_ms_2 = 0;
+    float old_temp = 9999;
     #ifdef CHAMBER_MINTEMP
       int16_t Temperature::mintemp_raw_CHAMBER = HEATER_CHAMBER_RAW_LO_TEMP;
     #endif
       }
     #endif
 
+    #if EITHER(CHAMBER_FAN, CHAMBER_VENT)
+      if (temp_chamber.target > CHAMBER_MINTEMP) {
+        flag_chamber_off = false;
+
+        #if ENABLED(CHAMBER_FAN)
+          #if CHAMBER_FAN_MODE == 0
+            fan_chamber_pwm = CHAMBER_FAN_BASE
+          #elif CHAMBER_FAN_MODE == 1
+            fan_chamber_pwm = temp_chamber.celsius > temp_chamber.target ? CHAMBER_FAN_BASE + ((temp_chamber.celsius - temp_chamber.target)  * CHAMBER_FAN_FACTOR ) : 0;
+          #elif CHAMBER_FAN_MODE == 2
+            fan_chamber_pwm = (CHAMBER_FAN_BASE) + (CHAMBER_FAN_FACTOR) * ABS(temp_chamber.celsius - temp_chamber.target);
+            if (temp_chamber.soft_pwm_amount)
+              fan_chamber_pwm += (CHAMBER_FAN_FACTOR) * 2;
+          #endif
+          fan_chamber_pwm = _MIN(225, fan_chamber_pwm);
+          thermalManager.set_fan_speed(2, fan_chamber_pwm); // TODO: instead of fan 2, set to chamber fan
+        #endif
+
+        #if ENABLED(CHAMBER_VENT)
+          #ifndef MIN_COOLING_SLOPE_TIME_CHAMBER_VENT
+            #define MIN_COOLING_SLOPE_TIME_CHAMBER_VENT 20
+          #endif
+          #ifndef MIN_COOLING_SLOPE_DEG_CHAMBER_VENT
+            #define MIN_COOLING_SLOPE_DEG_CHAMBER_VENT 1.5
+          #endif
+          if( (temp_chamber.celsius - temp_chamber.target >= HIGH_EXCESS_HEAT_LIMIT) && !flag_chamber_excess_heat) {
+          // open vent after MIN_COOLING_SLOPE_TIME_CHAMBER_VENT seconds
+          // if the temperature did not drop at least MIN_COOLING_SLOPE_DEG_CHAMBER_VENT
+            if (next_cool_check_ms_2 == 0 || ELAPSED(ms, next_cool_check_ms_2)) {
+              if (old_temp - temp_chamber.celsius < float(MIN_COOLING_SLOPE_DEG_CHAMBER_VENT)) flag_chamber_excess_heat = true; //the bed is heating the chamber too much
+              next_cool_check_ms_2 = ms + 1000UL * MIN_COOLING_SLOPE_TIME_CHAMBER_VENT;
+              old_temp = temp_chamber.celsius;
+            }
+          }
+          else {
+            next_cool_check_ms_2 = 0;
+            old_temp = 9999;
+          }
+          if (flag_chamber_excess_heat && (temp_chamber.celsius - temp_chamber.target <= -LOW_EXCESS_HEAT_LIMIT) ) {
+            flag_chamber_excess_heat = false;
+          }
+        #endif
+      }
+      else if (!flag_chamber_off) {
+        #if ENABLED(CHAMBER_FAN)
+          flag_chamber_off = true;
+          thermalManager.set_fan_speed(2, 0);
+        #endif
+        #if ENABLED(CHAMBER_VENT)
+          flag_chamber_excess_heat = false;
+          MOVE_SERVO(CHAMBER_VENT_SERVO_NR, 90);
+        #endif
+      }
+    #endif
+
     if (ELAPSED(ms, next_chamber_check_ms)) {
       next_chamber_check_ms = ms + CHAMBER_CHECK_INTERVAL;
 
       if (WITHIN(temp_chamber.celsius, CHAMBER_MINTEMP, CHAMBER_MAXTEMP)) {
-        #if ENABLED(CHAMBER_LIMIT_SWITCHING)
-          if (temp_chamber.celsius >= temp_chamber.target + TEMP_CHAMBER_HYSTERESIS)
-            temp_chamber.soft_pwm_amount = 0;
-          else if (temp_chamber.celsius <= temp_chamber.target - (TEMP_CHAMBER_HYSTERESIS))
-            temp_chamber.soft_pwm_amount = MAX_CHAMBER_POWER >> 1;
-        #else
-          temp_chamber.soft_pwm_amount = temp_chamber.celsius < temp_chamber.target ? MAX_CHAMBER_POWER >> 1 : 0;
-        #endif
+        if (!flag_chamber_excess_heat){
+          #if ENABLED(CHAMBER_LIMIT_SWITCHING)
+            if (temp_chamber.celsius >= temp_chamber.target + TEMP_CHAMBER_HYSTERESIS)
+              temp_chamber.soft_pwm_amount = 0;
+            else if (temp_chamber.celsius <= temp_chamber.target - (TEMP_CHAMBER_HYSTERESIS))
+              temp_chamber.soft_pwm_amount = (MAX_CHAMBER_POWER) >> 1;
+          #else
+            temp_chamber.soft_pwm_amount = temp_chamber.celsius < temp_chamber.target ? (MAX_CHAMBER_POWER) >> 1 : 0;
+          #endif
+          #if ENABLED(CHAMBER_VENT)
+            if (!flag_chamber_off) MOVE_SERVO(CHAMBER_VENT_SERVO_NR, 0);
+          #endif
+        }
+        else {
+          temp_chamber.soft_pwm_amount = 0;
+          #if ENABLED(CHAMBER_VENT)
+            if (!flag_chamber_off) MOVE_SERVO(CHAMBER_VENT_SERVO_NR, temp_chamber.celsius <= temp_chamber.target ? 0 : 90);
+          #endif
+        }
       }
       else {
         temp_chamber.soft_pwm_amount = 0;
       #define MIN_COOLING_SLOPE_DEG_CHAMBER 1.50
     #endif
     #ifndef MIN_COOLING_SLOPE_TIME_CHAMBER
-      #define MIN_COOLING_SLOPE_TIME_CHAMBER 60
+      #define MIN_COOLING_SLOPE_TIME_CHAMBER 120
     #endif
 
     bool Temperature::wait_for_chamber(const bool no_wait_for_cooling/*=true*/) {

Marlin/src/pins/stm32f4/pins_BTT_SKR_PRO_common.h

 // Servos
 //
 #define SERVO0_PIN                          PA1
+#define SERVO1_PIN                          PC9
 
 //
 // Trinamic Stallguard pins