97 lines
3.6 KiB
Python
97 lines
3.6 KiB
Python
#!/usr/bin/python3
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# -*- coding: utf-8 -*-
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import RPi.GPIO as GPIO
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from datetime import date
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from os import path
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from os import getenv
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import time
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import sys
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# Configuration
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FAN_PIN = getenv('RPI_FAN_PIN', 21) # BCM pin used to drive transistor's base
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WAIT_TIME = getenv('RPI_FAN_WAITTIME', 10) # [s] Time to wait between each refresh
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FAN_MIN = getenv('RPI_FAN_MIN', 80) # [%] Fan minimum speed.
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PWM_FREQ = getenv('RPI_FAN_PWMFREQ', 25000) # [Hz] Change this value if fan has strange behavior
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# Fan speed will change only of the difference of temperature is higher than hysteresis
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hyst = getenv('RPI_FAN_HYST', 1)
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debug = bool(getenv('RPI_FAN_DEBUG', 'False'))
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prom_collect_dir = getenv('RPI_PROM_COLLECTDIR','/tmp/textfile-collector')
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prom_collect_file = prom_collect_dir + '/rpi_fan.prom'
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# Configurable temperature and fan speed steps
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tempSteps = [60, 70, 75, 80] # [°C]
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speedSteps = [0, 80, 90, 100] # [%]
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# tempSteps = [40, 45]
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# speedSteps = [0, 100]
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# Setup GPIO pin
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GPIO.setmode(GPIO.BCM)
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GPIO.setup(FAN_PIN, GPIO.OUT, initial=GPIO.LOW)
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fan = GPIO.PWM(FAN_PIN, PWM_FREQ)
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fan.start(0)
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i = 0
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cpuTemp = 0
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fanSpeed = 0
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cpuTempOld = 0
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fanSpeedOld = 0
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if debug:
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print('%s Temp: %s, Fan: %s' % (date.today(), cpuTemp, fanSpeed))
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# We must set a speed value for each temperature step
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if len(speedSteps) != len(tempSteps):
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print('Numbers of temp steps and speed steps are different')
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exit(0)
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try:
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while 1:
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# Read CPU temperature
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cpuTempFile = open('/sys/class/thermal/thermal_zone0/temp', 'r')
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cpuTemp = float(cpuTempFile.read()) / 1000
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cpuTempFile.close()
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if debug:
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print('%s Temp: %s, Fan: %s' % (date.today(), cpuTemp, fanSpeed))
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# Calculate desired fan speed
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if abs(cpuTemp - cpuTempOld) > hyst:
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# Below first value, fan will run at min speed.
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if cpuTemp < tempSteps[0]:
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fanSpeed = speedSteps[0]
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# Above last value, fan will run at max speed
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elif cpuTemp >= tempSteps[len(tempSteps) - 1]:
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fanSpeed = speedSteps[len(tempSteps) - 1]
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# If temperature is between 2 steps, fan speed is calculated by linear interpolation
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else:
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for i in range(0, len(tempSteps) - 1):
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if (cpuTemp >= tempSteps[i]) and (cpuTemp < tempSteps[i + 1]):
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fanSpeed = round((speedSteps[i + 1] - speedSteps[i])
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/ (tempSteps[i + 1] - tempSteps[i])
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* (cpuTemp - tempSteps[i])
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+speedSteps[i], 1)
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if fanSpeed != fanSpeedOld:
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if (fanSpeed != fanSpeedOld
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and (fanSpeed >= FAN_MIN or fanSpeed == 0)):
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fan.ChangeDutyCycle(fanSpeed)
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fanSpeedOld = fanSpeed
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if path.isdir(prom_collect_dir):
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with open(prom_collect_file, 'w') as f:
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str = '#HELP rpi_fan fan running at percent duty cycle\n'
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str += '#TYPE rpi_fan gauge\n'
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str += 'rpi_fan{component="sys"} %s\n' % fanSpeed
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f.write(str)
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if debug:
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print('%s Temp: %s, Fan: %s' % (date.today(), cpuTemp, fanSpeed))
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cpuTempOld = cpuTemp
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# Wait until next refresh
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time.sleep(WAIT_TIME)
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except Exception as exception:
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print('Exception: {}'.format(type(exception).__name__))
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print('Exception message: {}'.format(exception))
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GPIO.cleanup()
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sys.exit()
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