shutdown.py

#!/usr/bin/python

import RPi.GPIO as GPIO
import time
import subprocess
from threading import Timer

GPIO.setmode(GPIO.BOARD)

# Time in seconds that power button must be held
SHUTDOWN_HOLD_TIME = 3 

# we will use the pin numbering to match the pins on the Pi, instead of the
# GPIO pin outs (makes it easier to keep track of things)
# use the same pin that is used for the reset button (one button to rule them all!)
GPIO.setup(5, GPIO.IN, pull_up_down = GPIO.PUD_UP)

def perform_shutdown():
    subprocess.call("shutdown -h now", shell=True,
    stdout=subprocess.PIPE, stderr=subprocess.PIPE)
    oldButtonState1 = buttonState1

oldButtonState1 = True

shutdown_timer = shutdown_timer = Timer(SHUTDOWN_HOLD_TIME, perform_shutdown)

while True:
    #grab the current button state
    buttonState1 = GPIO.input(5)

    # check to see if button has been pushed
    if buttonState1 != oldButtonState1 and buttonState1 == False:
        oldButtonState1 = buttonState1
        # shutdown
        shutdown_timer.start()
    else if buttonState1 != oldButtonState1 and buttonState1 == True:
        shutdown_timer.cancel()

    time.sleep(.5)