Temperature Controlled Raspberry Pi Fan (Keep Your Pi Within a Fixed Temperature Limits)

Hello | Hola | Bonjour | Zdravstvuyte | Other Hello's i dont know :P

Welcome all to the world of Raspberry pi.

Well after my grand success of earlier instructable of how to setup pi for dummies, here i am with you once again to cool your pi ! What ? you haven't watched my earlier instructable. don't panic find the link below :)

https://www.instructables.com/id/Setting-Up-Raspbe...

Well if you have watched my earlier tutorial, you might have understood how stubborn pi is ! So, one fine day he told me that "I won't function unless you cool me ! after all everyone need a bit comfort :P"

So finally we agreed on terms of adding a temperature controlled fan and heat sink. This is a step by step guide which will help you set up your Fan & Heat Sink in a very systematic way. A tutorial is also available on Youtube. I will not mind if you watch it :-) but if you do press the subscribe button please ! :-P

Well, most of you would think that this would be the end just paste the heat sink and attach the fan directly to the GPIO !

A big NOOOOOooooo!!!

My pi wanted something more.. he complained that the fan was running all the time at that gave him a very bad headache !

He demanded a fan that would :-

1. Run only when he is working

2. Help maintain his temperature limits within a fixed interval of time !

So, my pi selected this case ( said it was beautiful :-) )

For triggering the fan, you also require, one S8050 (PNP) transistor & a few connectors !

Connect your fan and transistor as shown in the schematic.

Here i have connected the base of transistor with GPIO 21.

Just like all great things !

We need a small script that would run continuously on pi and control the fan.

Just execute these commands on the terminal !

<p>sudo nano run-fan.py</p>

Go ahead and paste the following script in run-fan.py

#!/usr/bin/env python
import os
import time
import RPi.GPIO as GPIO
GPIO.setwarnings(False)
pin = 21 # The pin ID, edit here to change it
maxTMP = 40 # The high temperature in Celsius which will trigger the fan on
minTMP = 35 # The low temperature in Celsius which will trigger fan off
GPIO.setmode(GPIO.BCM)
GPIO.setup(pin, GPIO.OUT)
GPIO.setwarnings(False)
    
def getCPUtemperature():
    res = os.popen('vcgencmd measure_temp').readline()
    temp =(res.replace("temp=","").replace("'C\n",""))
    #print(temp)
    return temp
def getTEMP():
    CPU_temp = float(getCPUtemperature())
    if CPU_temp>maxTMP:
        GPIO.output(pin, True)
    elif CPU_temp<minTMP:
         GPIO.output(pin, False)
    return()
try:
    while True:
        getTEMP()
        time.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

Do modify the pinID ie. your GPIO no, upper & lower temperature limits as per the GPIO pin connected with the transistor base. Save and exit by pressing Cntrl X + Y;

Next, make this executable by running following commands

<p>sudo mv run-fan.py /usr/local/bin/</p><p>sudo chmod +x /usr/local/bin/run-fan.py</p>

Go ahead and create a new file run-fan.sh

sudo nano run-fan.sh

Next, paste the following code in the editor

#! /bin/sh
### BEGIN INIT INFO
# Provides:          run-fan.py
# Required-Start:    $remote_fs $syslog
# Required-Stop:     $remote_fs $syslog
# Default-Start:     2 3 4 5
# Default-Stop:      0 1 6
### END INIT INFO
# If you want a command to always run, put it here
# Carry out specific functions when asked to by the system
case "$1" in
  start)
    echo "Starting run-fan.py"
    /usr/local/bin/run-fan.py &
    ;;
  stop)
    echo "Stopping run-fan.py"
    pkill -f /usr/local/bin/run-fan.py
    ;;
  *)
    echo "Usage: /etc/init.d/run-fan.sh {start|stop}"
    exit 1
    ;;
esac
exit 0

Execute these commands to get the ball rolling !

sudo mv run-fan.sh /etc/init.d/
sudo chmod +x /etc/init.d/run-fan.sh

Now register the script to run on boot

sudo update-rc.d run-fan.sh defaults

But, but pi told me that the script is not yet started.

Oh ! get is working by executing the following command

sudo /etc/init.d/run-fan.sh start

The fan would has started and now you can jump from your chairs !

You really did great if your fan has started !

If not, you are the one who might have messed it up somewhere ! Re-watch the steps carefully :P

By the way my pi is happy with me now ! I gave him all the comfort he needs and now i make him work 24 X 7 Haha !

You all can clap now !

No wait don't close the window ! comment if you have any doubt !

Watch the complete tutorial on this link and do subscribe to Technoww so that i can start making millions :)