树莓派设置关机重启键

#!/usr/bin/env python3
# coding=utf-8

import RPi.GPIO as GPIO
import time
import os,sys
import signal
 
GPIO.setmode(GPIO..BOARD)

# 定义引脚7为关机重启键
pin_btn=7
 
GPIO.setup(pin_btn, GPIO.IN, pull_up_down=GPIO.PUD_UP)#默认下降沿触发
 
press_time=0
count_down=10
 
def cleanup():
    #释放资源，不然下次运行是可能会收到警告
    GPIO.cleanup()
 
def handleSIGTERM(signum, frame):
    sys.exit()#raise an exception of type SystemExit
 
def onPress(channel):
    global press_time,count_down
    press_time+=1
    if press_time >3:
        press_time=1
    elif press_time==3:
        count_down=10

#开始执行主函数，增加事件关联
#当引脚处于下降沿时，调用onPress函数，bouncetime用于消抖
GPIO.add_event_detect(pin_btn, GPIO.FALLING, callback= onPress,bouncetime=500)#默认下降沿触发

try:
    while True:
        if press_time==1:
            if count_down==0:
                print "start restart"
                os.system("shutdown -r -t 5 now")
                sys.exit()
            led_on=not led_on
            GPIO.output(pin_led, led_on)# blink led
        
        if press_time==2 and count_down==0:
            print "start shutdown"
            os.system("shutdown  -t 5 now")
            sys.exit()
 
        if press_time==1 or press_time==2:
            count_down-=1
            print "%s second"%(count_down)
        time.sleep(1)
except KeyboardInterrupt:
    print('User press Ctrl+c ,exit;')
finally:
    cleanup()

参考文献：
1.给树莓派添加重启关机按钮