Reset/Shutdown switch for Raspberry Pi

restart_shutdown_watcher.py

#!/usr/bin/env python2.7
# This script is meant to be used to monitor a button on the
# Raspberry Pi. I connected the button between pins 13 and 14,
# chosen because BCM 27 is not used for anything else and it is
# right next to a ground, so I can use a single connector. 
# 
# If the button is pressed breifly (less than 5 seconds), the Pi
# will reboot. If the button is held down longer, it will shut down (halt).
# After a halt, you will need to cycle power to restart.
#
# I needed this to use with Emulation Station / RetroPie, since some emulators can get
# "stuck" and I don't have a keyboard attached to the Pi. Restarting the
# Pi by power cycling is generally a bad idea due to data corruption on
# the SD card.
#
# I wrote this because other solutions on the web use a hard loop to poll the GPIO
# status, which seems like a waste of resources. Here I instead use interrupts, so this
# script just sleeps most of the time until woken up with the button press. I also did
# not see the button-driven shutdown function anywhere else.
#
# To use, add this line to /etc/rc.local
#   python /home/pi/restart_shutdown_watcher.py --silent &
#
# Assuming, of course, that you put the script in the pi home directory :)

from __future__ import print_function
import RPi.GPIO as GPIO  
import time, os

GPIO.setmode(GPIO.BCM)

# GPIO 27 set up as inputs, pulled up to avoid false detection.  
# Port is wired to connect to GND on button press,  
# so we'll be setting up falling edge detection.  
GPIO.setup(27, GPIO.IN, pull_up_down=GPIO.PUD_UP)

try: 
    # first wait for the button press
    GPIO.wait_for_edge(27, GPIO.FALLING, bouncetime=300)  
    press_time = time.time()
    # now wait for the rise (button let go)
    GPIO.wait_for_edge(27,GPIO.RISING,bouncetime=100,timeout=5001)
    if time.time() - press_time > 5.0:
        print("Shutdown")
        os.system("sudo shutdown -h now")
    else:
        print("Reboot")
        os.system("sudo shutdown -r now")
except KeyboardInterrupt:
    pass
GPIO.cleanup()           # clean up GPIO on normal exit