Uses a Raspberry Pi and a PIR (motion) sensor. Sends Mqtt messages when motion is detected.

mqtt_pir.py

#!/usr/bin/env python

from time import time, sleep
import datetime
import os	          # For running external commands
import RPi.GPIO as GPIO
import urlparse
import paho.mqtt.client as paho

# Time to wait (in seconds)
ttw=60*10
cttw=ttw

# Setup Gpio
GPIO.setwarnings(False)
GPIO.setmode(GPIO.BOARD)
GPIO.setup(13, GPIO.IN)         #Output from PIR motion sensor connected to pin 13

# Mqtt 
#mqttc = mosquitto.Mosquitto()
mqttc = paho.Client()

url_str = 'mqtt://192.168.1.79:1883'
url = urlparse.urlparse(url_str)
mqttc.username_pw_set("user", "password")

def sendmqtt(mess):
    #print "Send mqtt"
    now = datetime.datetime.now()
    mqttc.connect(url.hostname, url.port)
    mqttc.publish("pir/hallway", str(now) + mess)

while True:
    i=GPIO.input(13)
    if i==0:                 #When output from motion sensor is LOW, no movement
        cttw-=1
        #print cttw
        if cttw==0: # Counter has reached zero
            #print "Counter is 0"
            sendmqtt("Timeout")
            cttw=ttw    # Reset counter
            
    elif i==1:               #When output from motion sensor is HIGH, movement detected
        #print "Motion detected"
        cttw=ttw    # Reset counter
        sendmqtt("Motion!")
        sleep(1)    # Dont send to many messages
    sleep(1)