Joy-it 251187, Manual

Page: 9 / 11

www.joy - it.net
Pascalstr. 8 47506 Neukirchen - Vluyn
This program controls the fan speed based on the CPU temperature.
To run the program, you must first download the required library. This is
done with the following commands:
sudo apt - get update
sudo apt - get upgrade
sudo apt - get install python3 - pip
sudo pip3 install gpiozero RPi.GPIO
3. SOFTWARE FOR FAN CONTROL
from gpiozero import CPUTemperature, PWMLED
from time import sleep
led = PWMLED( 2 ) # PWM - Pin (GPIO2)
startTemp = 55 # Temperature at which the fan switches on
pTemp = 4 # Proportional part
iTemp = 0.2 # Integral part
fanSpeed = 0 # Fan speed
sum = 0 # variable for i part
while True : # Control loop
cpu = CPUTemperature() # Reading the current temperature values
actTemp = cpu.temperature # Current temperature as float variable
diff = actTemp - startTemp
sum = sum + diff
pDiff = diff * pTemp
iDiff = sum * iTemp
fanSpeed = pDiff + iDiff + 35
if fanSpeed > 100 :
fanSpeed = 100
elif fanSpeed < 35 :
fanSpeed = 0
if sum > 100 :
sum = 100
elif sum < - 100 :
sum = - 100
#print(str(actTemp) + "C, " + str(fanSpeed))
led.value = fanSpeed / 100 # PWM Output
sleep( 1 )