Generic Panic Button - Python Script, to execute commands. (see: https://gist.github.com/koenbollen/a87b3eca1e92f2dade70)

gpb.py

#!/usr/bin/env python
#
# Copyright (c) 2014, Koen Bollen <meneer@koenbollen.nl>
#
# Permission to use, copy, modify, and/or distribute this software for any purpose
# with or without fee is hereby granted, provided that the above copyright notice
# and this permission notice appear in all copies.
#
# THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES WITH
# REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND
# FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT,
# INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS
# OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER
# TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF
# THIS SOFTWARE.

from multiprocessing import Process
from subprocess import call
import argparse
import serial
import sys
import time

DEFAULT_PORT = '/dev/tty.OPIOT_BT_09-DevB'

def connect(port, tries=0, timeout=1):
	while True:
		try:
			return serial.Serial(port, 9600, timeout=timeout)
		except Exception, e:
			if tries > 0:
				tries -= 1
				if tries == 0:
					raise e
			time.sleep(.1)

parser = argparse.ArgumentParser(prog='gpb', description='Generic Panic Button')
parser.add_argument('command', type=str, nargs=1, help='the command to run')
parser.add_argument('argument', type=str, nargs='*', help='arguments to pass')
parser.add_argument('--verbose', '-v', action='store_true', help='more verbose output')
parser.add_argument('--once', '-o', action='store_true', help='only try and bluetooth connect once')
parser.add_argument('--quit', '-q', action='store_true', help='quit after first execute')
parser.add_argument('--event', '-e', type=str, default='down', help='on which event to execute: down, up, connect')
parser.add_argument('--connect', '-c', action='store_true', help='same as `--event connect`, implies --quit')
parser.add_argument('--blink', '-b', action='store_true', help='blink LED on ping')

args = parser.parse_args()
if args.connect:
	args.event = 'connect'
if args.event == 'connect':
	args.connect = True
	args.quit = True

if args.verbose:
	print(args)

def execute_sync():
	call(args.command+args.argument, shell=False)
def execute():
	p=Process(target=execute_sync)
	p.start()

if args.verbose:
	print('connecting...')

ser = None
try:
	try:
		ser = connect(DEFAULT_PORT, args.once and 1 or 0, 20)
	except Exception, e:
		print >>sys.stderr, 'failed to make a bluetooth connection:', e

	if args.verbose:
		print('connected')

	if args.event == 'connect':
		execute()
	else:
		last = 0
		quit = False
		while True:
			if ser.inWaiting() > 0:
				c = ser.read()
				run = False
				if c == 'D':
					if args.verbose:
						print('down')
					if args.event == 'down':
						run = True
				elif c == 'U':
					if args.verbose:
						print('up')
					if args.event == 'up':
						run = True
					if quit:
						break
				elif c == 'P':
					if args.verbose:
						print('pong')
				if run:
					execute()
					if args.quit:
						if args.event == 'down':
							quit = True
						else:
							break

			now = time.time()
			if now-last > 10:
				if args.verbose:
					print('ping')
				ser.write('P')
				if args.blink:
					ser.write('L')
				ser.flush()
				last = now

			time.sleep(0.1)

	if args.verbose:
		print('quit')
	ser.flush()
	time.sleep(0.9)
	ser.write('Q')
	ser.close()

except KeyboardInterrupt:
	if ser != None:
		ser.write('Q')
		ser.close()
	if args.verbose:
		print('quit')
	sys.exit()

# Sincerely,
# —Koen