this is to control a fan on a raspberry pi with python 3.4 on a bc332 transistor

fancontrol python 3.4 code

#!/usr/bin/env python3
# first author: Edoardo Paolo Scalafiotti <edoardo849@gmail.com>
# Edits done by: Marco Bosch <marcogithub@hotmail.com>

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

pin = 18 # The pin ID, edit here to change it
maxTMP = 49.0 # The maximum temperature in Celsius after which we trigger the fan
minTMP = 40.0 # Edit this sets the cutoff temperture.
global Fan #Edit this makes the variable Fan a global variable
Fan = 0 # Edit this variable is to help the script run for a time to get the temp down to what ever lower limit you set at minTMP

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

def getCPUtemperature():
    res = os.popen('vcgencmd measure_temp').readline()
    cput =(res.replace('temp=','').replace("\'C\n",""))
    #print ("temp is {0}".format(cput)) #Uncomment here for testing
    return cput   
def fanON():
    setPin(True)
    return()
def fanOFF():
    setPin(False)
    return()
def getTEMP():								#code by marco
    global Fan
    CPU_temp = float(getCPUtemperature())
    if Fan == 0:
        if CPU_temp > maxTMP:
            Fan = 1
            fanON()
        else:
            Fan = 0
            fanOFF()
    elif Fan == 1:
        if CPU_temp > minTMP:
            Fan = 1
            fanON()
        else:
            Fan = 0
            fanOFF()
    else:
        Fan = 0
        fanOFF()							#end
            
    return()
def setPin(mode): # A little redundant function but useful if you want to add logging
    GPIO.output(pin, mode)
    return()

try:
    setup()
    while True:
        getTEMP()
        sleep(5) # Read the temperature every 5 sec, increase or decrease this limit if you want
except KeyboardInterrupt: # trap a CTRL+C keyboard interrupt
    GPIO.cleanup()# resets all GPIO ports used by this program