树莓派温控风扇脚本（使用三极管 s8050）

Rehtt

September 26, 2017

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树莓派脚本

这里均以s8050为开关，s8050为NPN型三极管，以平的那面为参考面，左边阵脚接电源正极，中间针脚为开关，右边阵脚接电源负极

不控速风扇：
```python
#!/usr/bin/python
#coding:utf-8
import time

import RPi.GPIO as GPIO

#这里选择14（BCM）号针脚作为开关
GPIO_OUT = 14

def setup_GPIO():
    GPIO.setmode(GPIO.BCM)
    GPIO.setwarnings(False)
    GPIO.setup(GPIO_OUT, GPIO.OUT)

#开启风扇

def start_fan():
    GPIO.output(GPIO_OUT,GPIO.HIGH)

#关闭风扇

def stop_fan():
    GPIO.output(GPIO_OUT,GPIO.LOW)

#获取cpu温度

def cpu_temp():
    tempFile=open("/sys/class/thermal/thermal_zone0/temp")
    cpu_temp=tempFile.read()
    tempFile.close()
    temp_c=(int(cpu_temp)/1000)
    return int(temp_c)

#若温度大于等于55度开启风扇，小于等于45度关闭扇。中间相差温度作为缓冲，不然风扇就会一会开一会关。

def fen():
    if cpu_temp()>=55:
        start_fan()
        fen_state(1)

elif cpu_temp()<=45:
        stop_fan()
        fen_state(0)

else:
        pass

def fen_state(state):
    f=open("/etc/startup-script/state.txt")
    file=f.readlines()
    i=0
    for line in file:
        line = line.strip("\n")
        v = line.split(":")
        if v[0] == "fen_state":
            file[i] = "fen_state:"+str(state)
            break
        i=i+1
    f=open("/etc/startup-script/state.txt",'w+')
    f.writelines(file)
    f.close()

if __name__ == '__main__':
    setup_GPIO()
    fen_state(0)
    while True:
        fen()
        time.sleep(5)
```

控速风扇：
```python
#!/usr/bin/env python
# encoding: utf-8
import RPi.GPIO as GPIO
import time

#以14号(BCM)阵脚为开关
GPIO_OUT = 14
GPIO.setmode(GPIO.BCM)
GPIO.setwarnings(False)
GPIO.setup(GPIO_OUT,GPIO.OUT)
pwm = GPIO.PWM(GPIO_OUT, 100)

speed=0
prv_temp=0
try:
    while True:
        tmpFile=open('/sys/class/thermal/thermal_zone0/temp')
        cpu_temp=int(tmpFile.read())/1000
        tmpFile.close()
        if cpu_temp >= 34:
            if prv_temp < 34:
            # 启动时防止风扇卡死先全功率转0.1秒
                pwm.start(0)
                pwm.ChangeDutyCycle(100)
                time.sleep(.1)
            speed=min(cpu_temp, 100)
            pwm.ChangeDutyCycle(speed)
    else:
        pwm.stop()
    prv_temp=cpu_temp
    time.sleep(5)
except KeyboardInterrupt:
    pass
pwm.stop()
```

Last modification：October 23, 2019