controller_fan: Add support for a fan cooling the controller-board (#1070)

Whenever a stepper driver or a heater becomes active, it is desirable to turn on a fan cooling the associated parts on the controller board. This module implements such a fan that turns on whenever a stepper or specified heater turns on, decelerates to a configurable speed when all of the watched parts turn off, and returns to an off-speed, when a user-defined timeout is met.

Signed-off-by: Nils Friedchen <Nils.Friedchen@googlemail.com>

config/example-extras.cfg

@@ -414,6 +414,36 @@
 #   is 1.0
 
 
+# Controller cooling fan. A "controller fan" is a fan that will be
+# enabled whenever its associated heater or any configured stepper
+# driver is active. The fan will stop, whenever an idle_timeout is
+# reached to ensure no overheating will occur after deactivating a
+# watched component.
+#[controller_fan]
+#pin:
+#max_power:
+#shutdown_speed:
+#cycle_time:
+#hardware_pwm:
+#kick_start_time:
+#   See the "fan" section in example.cfg for a description of the
+#   above parameters.
+#idle_timeout:
+#   The ammount of time (in seconds) after a stepper driver or heater
+#   was active and the fan should be kept running. The default
+#   is 30 seconds.
+#idle_speed:
+#   The fan speed (expressed as a value from 0.0 to 1.0) that the fan
+#   will be set to when a heater or stepper driver was active and before
+#   the idle_timeout is reached. This must be greater or equal
+#   max_power. The default is max_power
+#heater:
+#   Name of the config section defining the heater that this fan is
+#   associated with. If a comma separated list of heater names is
+#   provided here, then the fan will be enabled when any of the given
+#   heaters are enabled. The default is "extruder".
+
+
 # Temperature-triggered cooling fans (one may define any number of
 # sections with a "temperature_fan" prefix). A "temperature fan" is a
 # fan that will be enabled whenever its associated sensor is above a

klippy/extras/controller_fan.py

@@ -0,0 +1,53 @@
+# Support a fan for cooling the MCU whenever a stepper or heater is on
+#
+# Copyright (C) 2019  Nils Friedchen <nils.friedchen@googlemail.com>
+#
+# This file may be distributed under the terms of the GNU GPLv3 license.
+import fan
+
+PIN_MIN_TIME = 0.100
+
+class ControllerFan:
+    def __init__(self, config):
+        self.printer = config.get_printer()
+        self.printer.register_event_handler("klippy:ready", self.handle_ready)
+        self.steppers = []
+        self.fan = fan.PrinterFan(config)
+        self.mcu = self.fan.mcu_fan.get_mcu()
+        self.max_power = config.getfloat(
+            'max_power', 1., minval=0., maxval=1.)
+        self.idle_speed = config.getfloat(
+            'idle_speed', self.max_power, minval=0., maxval=self.max_power)
+        self.idle_timeout = config.getint("idle_timeout", 30, minval=0)
+        self.heater_name = config.get("heater", "extruder")
+        self.last_on = self.idle_timeout
+    def handle_ready(self):
+        pheater = self.printer.lookup_object('heater')
+        self.heaters = [pheater.lookup_heater(n.strip())
+                        for n in self.heater_name.split(',')]
+        kin = self.printer.lookup_object('toolhead').get_kinematics()
+        self.steppers = kin.get_steppers()
+        reactor = self.printer.get_reactor()
+        reactor.register_timer(self.callback, reactor.NOW)
+    def callback(self, eventtime):
+        power = 0.
+        active = False
+        for stepper in self.steppers:
+            active |= stepper.is_motor_enabled()
+        for heater in self.heaters:
+            currentTemp, targetTemp = heater.get_temp(eventtime)
+            if targetTemp:
+                active = True
+        if active:
+            self.last_on = 0
+            power = self.max_power
+        else:
+            if self.last_on < self.idle_timeout:
+                power = self.idle_speed
+                self.last_on += 1
+        print_time = self.mcu.estimated_print_time(eventtime) + PIN_MIN_TIME
+        self.fan.set_speed(print_time, power)
+        return eventtime + 1.
+
+def load_config(config):
+    return ControllerFan(config)