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Zigbee, Z-Wave, Home Automation

It sounds so familiar.

 

Beta vs. VHS. MS-DOS vs. CPM-86. Blu-Ray vs. HDDVD.

 Another technology battle looms over us lowly end-users, and it feels like 1986 all over again. This time it’s all about home automation – that technology that allows us to turn on and off lights, appliances, home theatre and the like through our smartphone, Amazon Echo, Google home and others. Just like those early computer operating systems of the 80s, early, older standards (like X10), that connect home automation devices, have given way to two frontrunners – Zigbee and Z-wave.  

 Ok, so if you haven’t gone down this rabbit hole yet, you’re probably asking “why not just have home automation devices connect directly to Wi-Fi, and bypass having a second network like Zigbee of Z-wave”. Well, there are devices that connect in just that manner – and if you’re buying lots of them, they’re expensive – Z-wave and Zigbee offer a much cheaper radio interface compared to Wi-Fi. Also, imagine how many devices you’d have on you Wi-Fi network if you enabled every candidate device in your home? It might be over one hundred devices, clogging you router’s DHCP table – not to mention how many devices would have your Wi-Fi credentials.

 Now then, we’ve established that we want to have a separate network that sends simple commands to our lightbulbs, switches, doorbells, alarms and garage door openers. So how do they connect? Well, each system (Zigbee or Z-wave) will require some kind of ‘hub’ that connects on one side to your Wi-Fi or wired network, and on the other side to all the HA devices. You see where I’m going here?

 

So let’s look at the different kinds of HA environments:

 

X10

The granddaddy of all HA protocols is X10. Established way back in 1975, X10 used the actual AC power mains as a medium for control message transfer. That’s right – it sent the message between power outlets. This was pretty cool back in the disco era, but it was subject to the noise and interference that power mains often harbor. Missed ‘off’s’ and ‘on’s’ are common on X10, and interference can even cause false events. X10 is still around – it’s really cheap and very widely used in Europe, but it’s in decline.

 

Z-wave

Z-wave was first introduced back in 1999, and connects devices via radio signals in the 900mhz band. It uses “Mesh Networking”, and each device can optionally act as a repeater for other devices, as well and dedicated repeaters. A Z-wave bridge is required to connect the signals to the IP network (and consequently mobile devices). These devices are sometimes referred to as ‘smart hubs’, and may contain intelligence and scripts to group devices and provide an easy to use interface. Until late, more devices supported Z-wave than Zigbee, but Z-wave SOC chips are only produced by one company, Silicon Labs, and there are fears that they will control the market and keep prices high if Z-wave becomes the accepted standard. The advantage is that Silicon Labs have standards and rules that require every Z-Wave hub to work seamlessly with every Z-wave device. The Z-wave alliance is headed up by several large alarm companies, industrial automation firms and telecom conglomerates.  

Zigbee

The Zigbee specification was set back in 2004 for a low-cost, low-speed ad-hoc network to control home automation, medical devices and industrial devices using the 2.4Ghz radio band. It is an open standard run by the Zigbee Alliance. Many chip-fabs make Zigbee radio chips based on the standard, and no single company has control over the market (like Z-wave). But, it’s open-source, so there’s also no one officially making sure things work together. Amazon recently acquired a seat on the Zigbee alliance board, and this could influence the fight based on Amazon’s Echo (Which directly supports Zigbee radio).

 

So choosing a HA protocol feels like choosing a side - once again (remember deciding if you wanted a DOS computer or an Apple ][? (I guess I’m showing my age). Or blu-ray vs. HDDVD. The price of bad decision is a bunch of possibly obsolete stuff in the near future.

 

I chose Z-wave, based on the number of available devices that I wanted. My buddy Mark choose Zigbee, since he’s a developer and liked the open nature and generally cheaper devices. We both used little USB thumb-like dongles as radio bridges (Mark’s is plugged into a PC, mine is plugged into a Raspberry Pi running an open-source hub called OpenHab). We’ve both made significant investments in HA devices (switches, lights, etc). Who will prevail in the end? Well, your guess is as good as mine, though the recent Amazon development points to Mark making the right choice with Zigbee.

 

So what’s the bigger picture here? Well, imagine every light in an organization being on automation. Florescent tubes replaced with multi-color LED tubes that are normally white and indistinguishable from their predecessor, but can change color at will. Maybe cascading light fixtures that go red to guide students to safe areas in school emergencies; lights that can emit soothing colors during dental procedures and surgery prep; lights that can change in hue night to day to help night workers.

 

Streamwrite has begun R&D into adding automation control to portals – allowing the control of this new technology in the same intuitive and easy to use environment that our customer have come to love.

 

So, whoever wins the fight – Zigbee, Z-wave or something else, Streamwrite will have a hat in the automation ring!

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