树莓派自控风扇

简介

树莓派4b的自控风扇

主要信息

系统: Debian-Pi-Aarch64 2020-06-22-v2020-2.0-U4-Release BaseOS Plus++
三极管：S8050 NPN
连接线：杜邦线公对母，母对母

连接方式

风扇正极->5V
风扇负极->S8050 C
S8050-B-> Pi Pin12
S8050-E-> Pi GND

安装相应包

sudo apt-get install python-pip python-dev

pip install RPi.GPIO spidev

控制程序

#!/usr/bin/env python
# encoding: utf-8
import RPi.GPIO as GPIO
import time
GPIO.setwarnings(False)
GPIO.setmode(GPIO.BOARD)
GPIO.setup(12, GPIO.OUT)
pwm = GPIO.PWM(12, 100)
GPIO.setwarnings(False)
speed = 0
now_temp = 0
pwm.start(100)
logfile=open('/tmp/auto_temp.log','a')

def get_temp():
    tmpFile = open( '/sys/class/thermal/thermal_zone0/temp')
    temp=float(tmpFile.read())/1000
    tmpFile.close()
    return temp

while True:
    now_temp=get_temp()
    logfile.write(time.strftime('%Y-%m-%d %H:%M:%S',time.localtime(time.time()))+"   now_temp: "+str(now_temp)+"  speed:")
    if now_temp>=34:
        speed=min(int(now_temp-34)*5,100)
        logfile.write(str(speed)+'\n')
        logfile.flush()
        pwm.ChangeDutyCycle(speed)
    time.sleep(5)

开机自启

/etc/systemd/system/auto_temp.service

[Unit]
Description=Auto temp Service
After=network.target

[Service]
Type=simple
User=pi
ExecStart=python /home/pi/auto_temp.py
Restart=on-failure
SuccessExitStatus=3 4
RestartForceExitStatus=3 4

[Install]
WantedBy=multi-user.target

systemctl daemon-reload

systemctl enable auto_temp

systemctl start auto_temp