My Account

Wish List (0)

The PiBorg store is closed and we are unable to ship orders.
You will not be able to checkout any orders at this time.


Written by in Build, PicoBorg - Build on .

Nobody likes it when computers overheat, especially when you venture into the realms of over-clocking!

So we thought it would be great if you could setup a fan for a Raspberry Pi to work the same way they do in a laptop, turning on when it gets too hot and turning off again when it is sufficiently cooled. We have a drive control board, PicoBorg, which should be plenty capable of driving a PC style fan, and a small fan suitable for the task. The result was, a Python script which reads the current processor temperature and controls PicoBorg appropriately:

Here's the code, you can download the ChilledPi script file as text here Save the text file on your pi as Make the script executable using chmod +x and run using sudo ./

#!/usr/bin/env python
# coding: latin-1

# Import libary functions we need
import RPi.GPIO as GPIO
import time

# Set which GPIO pins the drive outputs are connected to
DRIVE_1 = 4
DRIVE_2 = 18
DRIVE_3 = 8
DRIVE_4 = 7

# Set all of the drive pins as output pins

# Map the on/off state to nicer names for display
dName = {}
dName[True] = 'ON '
dName[False] = 'OFF'

# Function to set all drives off
def MotorOff():
    GPIO.output(DRIVE_1, GPIO.LOW)
    GPIO.output(DRIVE_2, GPIO.LOW)
    GPIO.output(DRIVE_3, GPIO.LOW)
    GPIO.output(DRIVE_4, GPIO.LOW)

# Setup for processor monitor
lProcessorFans = [DRIVE_1]                              # List of fans to turn on when processor is too hot
pathSensor = '/sys/class/thermal/thermal_zone0/temp'    # File path used to read the temperature
readingPrintMultiplier = 0.001                          # Value to multiply the reading by for user display
tempHigh = 37000                                        # Reading at which the fan(s) will be started (same units as file)
tempLow = 33000                                         # Reading at which the fan(s) will be stopped (same units as file)
interval = 1                                            # Time between readings in seconds

    # Start by turning all drives off
    raw_input('You can now turn on the power, press ENTER to continue')
    fansOn = False
    while True:
        # Read the temperature in from the file system
        fSensor = open(pathSensor, 'r')
        reading = float(
        # Adjust fan(s) depending on current status
        if fansOn:
            if reading <= tempLow:
                # We have cooled down enough, turn the fans off
                for fan in lProcessorFans:
                    GPIO.output(fan, GPIO.LOW)
                fansOn = False
            if reading >= tempHigh:
                # We have warmed up enough, turn the fans on
                for fan in lProcessorFans:
                    GPIO.output(fan, GPIO.HIGH)
                fansOn = True
        # Print the latest reading and the current state of all 4 drives
        print '%02.3f %s %s %s %s' % (reading * readingPrintMultiplier, dName[GPIO.input(DRIVE_1)], dName[GPIO.input(DRIVE_2)], dName[GPIO.input(DRIVE_3)], dName[GPIO.input(DRIVE_4)])
        # Wait a while
except KeyboardInterrupt:
    # CTRL+C exit, turn off the drives and release the GPIO pins
    print 'Terminated'
    raw_input('Turn the power off now, press ENTER to continue')
Last update: Nov 05, 2017

Related Article

Related Products


Leave a Comment

Leave a Reply

The product is currently Out-of-Stock. Enter your email address below and we will notify you as soon as the product is available.