Joy-it RB-StromPi3-Case - Page 9

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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)