Add hardware PWM version

fan_hardware_pwm.py

@@ -0,0 +1,142 @@
+#!/usr/bin/python3
+
+### IMPORTANT ###
+# you must enable pwm chanels in /boot/config.txt
+# see https://github.com/Pioreactor/rpi_hardware_pwm
+
+# python modules
+from rpi_hardware_pwm import HardwarePWM
+import time
+import signal
+import sys
+import os
+import sys, getopt
+
+# Configuration
+PWM_CHANNEL = 0        # PWM channel used to drive PWM fan (gpio18 = channel 0)
+WAIT_TIME = 1           # [s] Time to wait between each refresh
+PWM_FREQ = 10000        # [Hz] 10kHz for Noctua PWM control
+
+# Configurable temperature and fan speed
+MIN_TEMP = 40
+MAX_TEMP = 60
+FAN_LOW = 20
+FAN_HIGH = 100
+FAN_OFF = 0
+FAN_MAX = 100
+
+# logging and metrics (enable = 1)
+VERBOSE = 0
+NODE_EXPORTER = 0
+
+# parse input arguments
+try:
+   opts, args = getopt.getopt(sys.argv[1:],"hv",["min-temp=","max-temp=","fan-low=","fan-high=","wait-time=","help","pwm-channel=","pwm-freq=","verbose","node-exporter"])
+except getopt.GetoptError:
+   print('fan.py [--min-temp=40] [--max-temp=70] [--fan-low=20] [--fan-high=100] [--wait-time=1] [--pwm-channel=0] [--pwm-freq=10000] [--node-exporter] [-v|--verbose] [-h|--help]')
+   sys.exit(2)
+for opt, arg in opts:
+   if opt in ("-h", "--help"):
+      print('fan.py [--min-temp=40] [--max-temp=70] [--fan-low=20] [--fan-high=100] [--wait-time=1] [--pwm-channel=0] [--pwm-freq=10000] [--node-exporter] [-v|--verbose] [-h|--help]')
+      sys.exit()
+   elif opt in ("-v", "--verbose"):
+      VERBOSE = 1
+   elif opt in ("--min-temp"):
+      MIN_TEMP = int(arg)
+   elif opt in ("--max-temp"):
+      MAX_TEMP = int(arg)
+   elif opt in ("--fan-low"):
+      FAN_LOW = int(arg)
+   elif opt in ("--fan-high"):
+      FAN_HIGH = int(arg)
+   elif opt in ("--wait-time"):
+      WAIT_TIME = int(arg)
+   elif opt in ("--pwm-channel"):
+      PWM_CHANNEL = int(arg)
+   elif opt in ("--pwm-freq"):
+      PWM_FREQ = int(arg)
+   elif opt in ("--node-exporter"):
+      NODE_EXPORTER = 1
+print("")
+print("MIN_TEMP:",MIN_TEMP)
+print("MAX_TEMP:",MAX_TEMP)
+print("FAN_LOW:",FAN_LOW)
+print("FAN_HIGH:",FAN_HIGH)
+print("WAIT_TIME:",WAIT_TIME)
+print("PWM_CHANNEL:",PWM_CHANNEL)
+print("PWM_FREQ:",PWM_FREQ)
+print("VERBOSE:",VERBOSE)
+print("NODE_EXPORTER:",NODE_EXPORTER)
+print("")
+
+# Get CPU's temperature
+def getCpuTemperature():
+    res = os.popen('cat /sys/devices/virtual/thermal/thermal_zone0/temp').readline()
+    temp = (float(res)/1000)
+    return temp
+
+# Set fan speed
+def setFanSpeed(speed,temp):
+    pwm.change_duty_cycle(speed)
+
+    # print fan speed and temperature
+    if VERBOSE == 1:
+        print("fan speed: ",int(speed),"    temp: ",temp)
+
+    # write fan metrics to file for node-exporter/prometheus
+    if NODE_EXPORTER == 1:
+        # Save a reference to the original standard output
+        original_stdout = sys.stdout 
+        with open('/var/lib/node_exporter/fan-metrics.prom', 'w') as f:
+            # Change the standard output to the file we created.
+            sys.stdout = f 
+            print('raspberry_fan_speed ',speed)
+            print('raspberry_fan_temp ',temp)
+            print('raspberry_fan_min_temp ',MIN_TEMP)
+            print('raspberry_fan_max_temp ',MAX_TEMP)
+            print('raspberry_fan_fan_low ',FAN_LOW)
+            print('raspberry_fan_fan_high ',FAN_HIGH)
+            print('raspberry_fan_wait_time ',WAIT_TIME)
+            print('raspberry_fan_pwm_channel ',PWM_CHANNEL)
+            print('raspberry_fan_freq ',PWM_FREQ)
+            # Reset the standard output to its original value
+            sys.stdout = original_stdout
+            f.close()
+
+    return()
+
+# Handle fan speed
+def handleFanSpeed():
+    temp = getCpuTemperature()
+
+    # Turn off the fan if temperature is below MIN_TEMP
+    if temp < MIN_TEMP:
+        setFanSpeed(FAN_OFF,temp)
+
+    # Set fan speed to MAXIMUM if the temperature is above MAX_TEMP
+    elif temp > MAX_TEMP:
+        setFanSpeed(FAN_MAX,temp)
+
+    # Caculate dynamic fan speed
+    else:
+        step = (FAN_HIGH - FAN_LOW)/(MAX_TEMP - MIN_TEMP)   
+        delta = temp - MIN_TEMP
+        speed = FAN_LOW + ( round(delta) * step )
+        setFanSpeed(speed,temp)
+
+    return ()
+
+try:
+    # Setup hardware PWM 
+    pwm = HardwarePWM(pwm_channel=PWM_CHANNEL, hz=60)
+    pwm.change_frequency(PWM_FREQ)
+    pwm.start(FAN_LOW) # full duty cycle
+
+    # Handle fan speed every WAIT_TIME sec
+    while True:
+        handleFanSpeed()
+        time.sleep(WAIT_TIME)
+
+except KeyboardInterrupt: # trap a CTRL+C keyboard interrupt
+    setFanSpeed(FAN_LOW,MIN_TEMP)
+