Pi Fan Tem Ctl

fanctl_pwm.py

#!/usr/bin/env python
# encoding: utf-8

import RPi.GPIO as GPIO
import time

fan_pin = 7
alert_temp = 48000
speed = 0
prv_temp = 0

GPIO.setwarnings(False)
GPIO.setmode(GPIO.BOARD)
GPIO.setup(fan_pin,GPIO.OUT)
pwm = GPIO.PWM(fan_pin,100)

try:
	while True:
		tf = open('/sys/class/thermal/thermal_zone0/temp')
		cpu_temp = int(tf.read())
		print(cpu_temp)
		tf.close()
		if cpu_temp >= alert_temp:
			if prv_temp < alert_temp:
				pwm.start(0)
				pwm.ChangeDutyCycle(100)
				time.sleep(0.1)
			speed = max(10,min(cpu_temp / 20 - 2400, 100))
			#print(speed)
			pwm.ChangeDutyCycle(speed)
		else:
			pwm.stop()
		prv_temp = cpu_temp

		time.sleep(5)

except KeyboardInterrupt:
	pass
pwm.stop()
GPIO.cleanup()
exit()