1 files changed, 39 insertions, 0 deletions
diff --git a/klippy/extras/fan.py b/klippy/extras/fan.py
new file mode 100644
index 00000000..c7434ca5
--- /dev/null
+++ b/klippy/extras/fan.py
@@ -0,0 +1,39 @@
+# Printer cooling fan
+#
+# Copyright (C) 2016-2018  Kevin O'Connor <kevin@koconnor.net>
+#
+# This file may be distributed under the terms of the GNU GPLv3 license.
+import pins
+
+FAN_MIN_TIME = 0.1
+PWM_CYCLE_TIME = 0.010
+
+class PrinterFan:
+    def __init__(self, config):
+        self.last_fan_value = 0.
+        self.last_fan_time = 0.
+        self.max_power = config.getfloat('max_power', 1., above=0., maxval=1.)
+        self.kick_start_time = config.getfloat('kick_start_time', 0.1, minval=0.)
+        printer = config.get_printer()
+        self.mcu_fan = pins.setup_pin(printer, 'pwm', config.get('pin'))
+        self.mcu_fan.setup_max_duration(0.)
+        self.mcu_fan.setup_cycle_time(PWM_CYCLE_TIME)
+        self.mcu_fan.setup_hard_pwm(config.getint('hard_pwm', 0))
+    def set_speed(self, print_time, value):
+        value = max(0., min(self.max_power, value))
+        if value == self.last_fan_value:
+            return
+        print_time = max(self.last_fan_time + FAN_MIN_TIME, print_time)
+        if (value and value < self.max_power
+            and not self.last_fan_value and self.kick_start_time):
+            # Run fan at full speed for specified kick_start_time
+            self.mcu_fan.set_pwm(print_time, self.max_power)
+            print_time += self.kick_start_time
+        self.mcu_fan.set_pwm(print_time, value)
+        self.last_fan_time = print_time
+        self.last_fan_value = value
+
+def load_config(config):
+    if config.get_name() != 'fan':
+        raise config.error("Invalid print cooling fan config name")
+    return PrinterFan(config)