#!/usr/bin/python
# shutdown a Raspberry pi under control from a GPIO pin
# Based on a script by George on the Ham Nation video series
# Modified by G. Forrest Cook, W0RIO
#
# Run this script from the /etc/rc.local file:
# /home/pi/bin/PiShutdown.py &
#
# Note that the Pi GPIO input pins are very noise-sensitive, even with the
# internal pull-up enabled.  GPIO inputs should be controlled by a spdt switch
# with the ends connected to the ground and +3V rails, or to a transistor with
# an external pull-up resistor tied to +3.3V so that the input always has a
# low impedances path to the rails.
#
# Pins used on the 40 pin Raspberry Pi header:
# 1 - +3.3V:	switch N.C. or an external pull-up resistor on GPIO 23
# 14 - Ground:	switch N.O. or reference ground for external transistor emitter
# 16 - GPIO 23: shutdown switch center or external transistor collector

import RPi.GPIO as gpio
import time
import os

SHUTDOWN_PIN = 23

gpio.setmode(gpio.BCM)
gpio.setup(SHUTDOWN_PIN, gpio.IN, pull_up_down = gpio.PUD_UP)

def Shutdown(channel):
  os.system("shutdown -h now")

gpio.add_event_detect(SHUTDOWN_PIN, gpio.FALLING, callback = Shutdown, bouncetime = 500)

while 1:
  time.sleep(1)