Raspberry pie realizes intelligent cooling by temperature control fan

Raspberry pie with shell , But he always makes a lot of noise , Then we can transform it , So that he can become a controllable fan , Realize a temperature control function

Materials needed

• triode S8550 PNP type ： Two dollars more than fifty
• DuPont bus to bus
• DuPont line male to female

these tb You can buy , There is a shop with parcel post

Then introduce these things
The triode faces the plane towards itself , There are three pins , Left to right are E、B、C. Popular said E It's positive ,C Yes , Equivalent to diode , Base level B Low level is the only way to turn on the circuit .

Then there is the raspberry pie pin , There are forty pins , Here you can see that there are two kinds of codes , When writing code, you need to specify what kind of coding method is available , The corresponding pin is to put the network cable socket of raspberry pie downward , Corresponding pin sequence

Wiring way
The red color of the fan is the positive pole , Connect to 5V,4 No. pin
Here, connect the triode to the negative pole of the fan , That is, the black line of the fan is connected to the... Of the triode C level
Transistor's E Level connection 6 Pin No , Grounding
Base stage of triode B Connect 8 Interface No , That is to say BCM Coded GPIO 14 Pin No

Start up after connecting , It seems that the fan will be powered on intermittently during startup , No big problem .
After power on , stay python Try to execute the command at the terminal , First, you need to install the library
apt install RPi.GPIO
perform python

GPIO_OUT=14

GPIO.setmode(GPIO.BCM)
GPIO.setwarnings(False)
GPIO.setup(GPIO_OUT,GPIO.OUT,initial=GPIO.HIGH)
self.Status=False
# start-up 
GPIO.output(GPIO_OUT,GPIO.LOW)
# close 
GPIO.output(GPIO_OUT,GPIO.HIGH)

Then you can execute the following command to check the temperature of raspberry pie , The output value is divided by 1000 Is the current temperature

cat /sys/class/thermal/thermal_zone0/temp

Last , This is a script , The fan can be controlled according to the temperature , The temperature exceeds 50 Open when , lower than 45 Close when , You can set it yourself , You can also set one here

import subprocess
import RPi.GPIO as GPIO
import time

class FanController:
    def __init__(self,GPIO_PIN):
        self.GPIO_OUT=GPIO_PIN
        GPIO.setmode(GPIO.BCM)
        GPIO.setwarnings(False)
        GPIO.setup(self.GPIO_OUT,GPIO.OUT,initial=GPIO.HIGH)
        self.Status=False
    def action(self,flag):
        if flag=='start':
            GPIO.output(self.GPIO_OUT,GPIO.LOW)
            self.Status=True
        elif flag=='stop':
            GPIO.output(self.GPIO_OUT,GPIO.HIGH)
            self.Status=False
def getTemp():
    Temp=subprocess.getoutput('cat /sys/class/thermal/thermal_zone0/temp')
    Temp=int(Temp)/1000
    print(time.strftime('%Y-%m-%d %H:%M-%S')+'\ttemp is %s oC' % (str(Temp)))
    return Temp
Fan=FanController(14)
print('start temp controller program')

while True:
    Temp=getTemp()
    if Temp>50 and not Fan.Status:
        print('temp is higher than 50 , fan will start')
        Fan.action('start')
    elif Temp<45 and Fan.Status:
        print('temp is less than 45 , fan will stop')
        Fan.action('stop')
    time.sleep(15)

Reference link
Raspberry pie — Use triode to control cooling fan