manage_fan.py

#!/usr/bin/env python3
"""
Script to regulate a 5v fan.
For wiring, see https://hackernoon.com/how-to-control-a-fan-to-cool-the-cpu-of-your-raspberrypi-3313b6e7f92c
#Author: Edoardo Paolo Scalafiotti <edoardo849@gmail.com>
# Modified by Egon Rijpkema
"""

import os
from time import sleep
import RPi.GPIO as GPIO

pin = 18  # The pin ID, edit here to change it
max_temp = 75  # When to start fan.
shutoff_temp = 50  # Temperature at which we stop the running fan


def setup():
    GPIO.setmode(GPIO.BCM)
    GPIO.setup(pin, GPIO.OUT)
    GPIO.setwarnings(False)


def get_temp():
    res = os.popen('vcgencmd measure_temp').readline()
    temp = (res.replace("temp=", "").replace("'C\n", ""))
    print("temp is {0}".format(temp))
    return float(temp)


def fan_on():
    GPIO.output(pin, True)
    

def fan_off():
    GPIO.output(pin, False)


def regulate_temp():
    CPU_temp = get_temp()
    if CPU_temp > max_temp:
        fan_on()
    elif CPU_temp < shutoff_temp:
        fan_off()


if __name__ == '__main__':
    try:
        setup()
        while True:
            regulate_temp()
            sleep(5)
    except KeyboardInterrupt:  # trap a CTRL+C keyboard interrupt
        GPIO.cleanup()  # resets all GPIO ports used by this program