Is Zigbee Right For Your Smart Home?
When I started down the smart home path, I have to admit I didn’t have a clue where it would lead. I was just looking for some neat ways to automate things and add efficiency to our home. But as I added new devices I began to better understand the ecosystem and the dependence those devices have on connectivity. There are so many different smart home devices out there now, and a variety of ways to connect to these devices — WiFi, Bluetooth, Z-Wave, Zigbee …
As I’ve done more research on how I want our new home’s technology to operate, I’m seriously considering some of the less obvious ways smart home devices communicate. Here, I’ll outline the advantages, disadvantages and applications in home automation with Zigbee.
To kick it off, let me explain what Zigbee is — a network protocol based on the IEEE.802.15.4 specification, a standard for low-rate wireless personal area networks (WPANs). Zigbee expands on the IEEE specification by adding mesh network and security layers along with an application framework to become a full-stack, certifiable, interoperable solution. That description sounds pretty complicated but basically means it’s a wireless protocol that transmits small amounts of data between devices securely.
A Zigbee device typically has four layers — the IEEE.802.15.4 Radio, Zigbee Pro, Zigbee Cluster Library and Zigbee Certification. Zigbee Pro is the network infrastructure, implementing features ranging from communication band specification and pair mechanisms to security key generation and power saving. The Zigbee Cluster Library is the application layer, which is used to define clusters that are standard sets of messages and device behaviors to allow Zigbee devices to behave in a standard manner across devices. This helps with interoperability, so Zigbee devices from different manufacturers can work with each other, basically standards based.
Zigbee devices typically communicate over 2.4GHz, but they can also communicate in sub-GHz bands, which are region-specific. Zigbee can transmit anywhere from 10 to 100 meters over 2.4GHz which makes it ideal for smart home use. It can transmit up to 1km on the sub-GHz bands. Since WiFi also uses 2.4GHz, Zigbee devices handle interference over 2.4GHz by using 16 separate channels of communication. They also automatically retransmit data as well as send a low number of data packets, making transmission failure unlikely. To me this is one of the downsides of Zigbee as 2.4GHz can get pretty crowded with signals as 2.4GHz is a common protocol for many smart home devices.
But Zigbee is interoperable, which means that two different Zigbee devices are capable of communicating with each other directly over the Zigbee network. In other words, mesh networking. While there are limits to interoperability due to multiple application profiles, such as Home Automation and Smart Energy, Zigbee’s device interoperability is still a very useful feature.
Zigbee is capable of forming various arrangements of networks connectivity between its devices. The most common network topologies are star, cluster tree and mesh. And Zigbee networks can consist of three types of devices: end device, router, and coordinator. A coordinator is responsible for creating the network as well as routing traffic through it. A network can only have one coordinator. A router is responsible for routing traffic, and an end device sounds like exactly what it is — end of the signal and does not route traffic through the network.
Zigbee’s main advantage over other network protocols like WiFi is that it’s very low power. This is a result of it being IEEE.802.15.4 standard plus the Zigbee protocol allows for lower power operation. While this means that Zigbee devices may not have a high range or push through much data, they save power, cost and maintenance. Zigbee even has a Green Power feature, which allows battery-less devices to join the network. According to the Connectivity Standards Alliance, Green Power takes advantage of the energy used to flip a typical light switch via common energy harvesting techniques, which is powerful enough to send commands through a Zigbee PRO network.
Understanding how Zigbee devices connect, Zigbee’s application for smart home automation is ideal. Zigbee devices in the home environment come out of the box with a mesh network where most devices are generally within the 10 to 100 meter range of each other. It’s nice to know that you can expand your home automation with Zigbee devices that will connect into your existing mesh network. Currently, the Connectivity Standards Alliance site lists about 400 devices for home automation — all common smart home devices such as light bulbs, switches, locks, motion sensors and thermostats.
There are major companies like Samsung, Bosch, Honeywell, Texas Instruments and Amazon that are making Zigbee products. Amazon’s Echo Plus came with a built-in Zigbee hub to control Zigbee devices. Samsung’s SmartThings devices use Zigbee as well to communicate (they also support Z-wave). It’s good to see that Zigbee has support from major companies and a wide range of devices.
As you can see, Zigbee devices can easily be added to a network, like a home mesh network, even running other protocols like WiFi, Bluetooth and Z-Wave, to communicate with each other. It’s ideal for applications such as home automation, where devices don’t communicate frequently and are in close range of each other. Zigbee’s built-in power saving is a great feature that allows devices to last on battery much longer than other network protocols.
Zigbee is just one option but it does bring a lot to the table in support of your smart home. One of my favorite aspects is that Zigbee does not require an internet connection to function. This means that you can still control your smart home devices even if your internet goes down or you want to limit your exposure to online threats and data breaches. This takes advantage of the lower latency type operations typical of more commercial edge computing networks.
In most cases, smart home networks usually consist of a mix of all these different type networks. But building in resiliency, especially with basic smart home devices like light bulbs, switches, locks and thermostats, helps ensure operations. Doing a little homework around smart home design and the devices you invest in can set you up for the long haul.
Let Debbie and I know what you think in the comments, DMs and emails as we really enjoy hearing from you. Thanks again to all those following Debbie and I through our home building journey. It’s great to hear your success stories and suggestions as we move through the process. And if you like the content I’m posting each week, don’t forget to ‘Like’ and ‘Follow.’
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