
![Smart home tracks network
devices](/images/uploads/2011/01/NetworkTracker-1024x196.png "Smart home tracks network devices")

One surprisingly useful component of my home automation system is its
ability to track every device that ever connects to the router at home
by mac address.

Every few minutes my smart home scans the local subnet looking for
connected devices. It does this by pinging each IP address in the local
address range and whenever it finds a device it gets its mac address and
compares it to a list of known mac addresses. Once it's found a device
it pings it more frequently to check that it's still connected to the
network.

Whenever it finds a new device (for example, a friend visiting with a
cell phone or laptop that connect to Wifi) it can ask for that device to
be identified (using the chat interface) and can track its comings and
goings from then on. If you happen to enter the house with a smart phone
with Wifi turned on you have just become an unwitting part of my
experiment and your phone's mac address will be tracked from here on
out.

Many consumer electronic devices now connect to the internet and each is
thus tracked by the home automation system to determine how long it has
been on for each day. This is used to calculate the instantaneous power
consumption of the home along with the lights and other devices that the
home automation can control or monitor.

**Aside from estimating power consumption and tracking visitors to the
house, one of the most useful aspects of this feature is that it's great
for finding lost devices.** Did your child lose their iPod touch at home
or is it at a friend's house? A quick look at the log shows when it was
last seen in the house confirming that it's still inside somewhere.
Ultimately it might be able to cross-reference which rooms were occupied
with when the device was last seen and thus give you an idea which couch
or bedroom to go search (future feature), but for now, at least you know
you aren't searching in vain. Ideally I'd have three access points with
firmware that can track the signal strength of each device in the home
so I can locate it more precisely but I haven't found a router offering
that capability yet. My laptop can track and report how far away from
the router it is but that's not as useful as being able to track
individual devices from the router.

Another possible use for this is **tracking screen time** - how many
hours did your kids spend watching TV or playing on the XBox when they
were in fact meant to be working on their homework? etc. etc. Of course
at some point this may all become a bit too Orwellian but as I've
mentioned before, part of the experiment I've been conducting with my
home automation is 'technical' but the larger portion is 'social' -
which features are genuinely useful and which are just too much.


Smart home tracks network devices by mac address


<img alt="Open Mesh routers" src="/images/uploads/2010/03/OpenMesh.png" />
>Open Mesh routers connecting house and barn


To get wifi access in our barn I wanted an affordable outdoor wifi link.
 During my research I came across http://open-mesh.com and purchased a
couple of their wireless access points.  Not only are they very
affordable ($49) but they have great functionality.  Setup was easy
using their web-based management console.  It even includes a map view
which shows the location of each node and its current status and the
status of all links.  My current 'mesh' network isn't much of a mesh
since it only has two nodes so I'm not likely to need the map view to
track them down.  Open-mesh will release a transparent bridge option
soon and then I'll be able to stream video from barn to house and out to
the internet, until then their excellent security means I'm unable to
stream video out to the internet.  Apart from that one missing feature
it does everything I want and a whole lot more.  One nice feature is the
ability to have two SSIDs - an open one that anyone can use and a
private, secure one.  You can even set up billing and charge your
visitors or neighbors to use your open wifi connection.


The Blog of Ian Mercer.

Topic: networking

Smart home tracks network devices by mac address

Open-Mesh routers provide an outdoor link