Where to start?

The first challenge was getting data from my phone on public networks to my private MQTT server. At home I run Mosquitto for handling any message brokering, particularly with Domoticz and Node-Red pushing messages around.

I won’t go into the details, but suffice to say I have Mosquitto at home, and Mosquitto on a server I rent in OVH. The one in OVH is TLS, and protected by a username and password. It is this server to which Owntracks is configured to push messages to.

In turn, the two Mosquitto servers are bridged, as per http://e.verything.co/post/62163759361/bridging-two-mqtt-brokers and http://owntracks.org/booklet/guide/bridge/ in order for the topic to which the phone publishes to be available internally at home.

The end result of this is the periodic announcement of my phones location on my internal home network

mqttitude/bagpuss_thecat/galaxys2 {“_type”: “location”, “lat”: “55.9182683”, “lon”: “-4.2232088”, “tst”: “1457045018”, “acc”: “20.0”, “batt”: “48”}

From here, it gets ingested into Node-Red by firstly subscribing to the mqttitude/bagpuss_thecat/galaxys2 topic, then the JSON is parsed out, and then it’s processed by a couple of node-red-node-geofence nodes in order to determine if the phone is in a certain location or not. These simply return the msg.location.isat parameter if the device matches any of the geofences.

Depending on the status of the .isat parameter, I then use the multiple messages feature of node-red to send messages to each of my Domoticz switches to alter their state.

if ( msg.location.isat == "Home") {
var home = { payload:'{"idx":181,"nvalue":1}' };
var work = { payload:'{"idx":180,"nvalue":0}' };
} else if ( msg.location.isat == "Work") {
var home = { payload:'{"idx":181,"nvalue":0}' };
var work = { payload:'{"idx":180,"nvalue":1}' };
} else {
var home = { payload:'{"idx":181,"nvalue":0}' };
var work = { payload:'{"idx":180,"nvalue":0}' };
return [ [ work, home ] ];

As you can see from the above code, the Domoticz IDX of the switch to say that I’m at work is 180, Home is 181, and I can then use those dummy switch states in Domoticz to do additional logic within the home automation system.