119
make.co
Take control of smart
home gadgets — and
revive those zombie
bulbs — with a Z-Wave
hat for Raspberry Pi
Written by Sean Nolan
Wi-Fi components can be expensive and power-
hungry, creating space for a bunch of different
protocols. With the X10 protocol fading into
history, there are really two that stand out: Zigbee
and Z-Wave. This is very much a Coke vs. Pepsi
kind of thing — there are a few differences, but
for the most part both Z* systems are the same
thing solving the same problems:
• Both rely on a gateway to coordinate
communication on the network. This is typically
a dedicated hardware unit that keeps an
inventory of devices, sends them commands,
and receives status updates. The gateway
is also the face of the Z* network to the
outside world — usually over Wi-Fi, using an
embedded webserver, a cloud service, or both.
• Both are mesh networks, which is quite handy
in the home environment. Z* signals can only
travel about 20–30 meters (65–100 feet), but
each node acts as a relay to pass messages
along to devices further away (Figure
A
).
Because of the way they’re evenly spread
throughout a house, lighting devices are
particularly well-suited to this kind of network.
The differences aren’t super important. Zigbee
enables more hops between nodes and more
devices on the network; Z-Wave has a longer
reach between nodes and is cheaper. Amazon’s
Echo Plus has a built-in Zigbee gateway, so that’s
nice. But both are perfectly serviceable; just
make sure you’re buying devices that match the
technology in your gateway! There are a few that
contain chips for both protocols if you really want
to run both.
Make a RaZberry Gateway
Of course I didn’t know much of this at first. My
first step to recover my Wink-abandoned lights
was to get out the ladder, climb up, and take a
look. It turns out that most of my lights were
manufactured by GoControl — pretty neat units
that slide right into an existing 6-inch ceiling can
(Figure
B
). Most importantly, that little Z-Wave
logo told me where to start!
A few hours of googling didn’t really point at an
“obvious choice” for a new Z-Wave gateway. The
closest is probably Aeotec SmartThings hardware
with open source Home Assistant control
Sean Nolan, Z-Wave.Me
software. That’d be a fine choice, but I wanted
to get a little closer to the metal and control my
destiny by building something myself. It turns out
that the RaZberry daughter board for Raspberry
Pi delivers excellent Z-Wave capability and is fully
programmable. Perfect!
The RaZberry (Figure
C
) also comes with a
license for Z-Way, a software stack that includes
everything from a low-level C API up through a
user-facing home control cloud service and user
interface. Getting it all built out was my first order
of business, and was pretty straightforward. You
can find more details on the following steps in the
Resources links at the end of the article.
A
RAZBERRY
RESCUE
B
C
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