What Is Zigbee Technology And How Does It Work?

What is Zigbee?

Simply put, Zigbee is a wireless protocol that is used to allow Smart Devices such as light bulbs, sockets, plugs, smart locks, motion sensors and door sensors to communicate with each other over a “PAN” (Personal Area Network).

As a standalone entity you can use this PAN as-is with devices including remote controls, battery powered wall switches and keyfobs for simple control purposes. It won’t be particularly smart, but for simple tasks such as turning on the light without getting up to use a light switch it will work perfectly.

If you connect the Zigbee network to a Smart Home Controller (such as one from SmartThings, Hubitat or Homey) then the full potential of Home Automation will be unleashed!

Why Use Zigbee?

No Smart Home protocol can claim to be perfect or the best suited to any particular application, so it’s worth remembering that choosing a Smart Home Controller that supports multiple protocols (such as Zigbee, Z-Wave & WiFi) as well as having integrations for other proprietary and Cloud based services is the best course of action for most people.

Why Use Zigbee

That said, Zigbee does have a number of compelling reasons for it to be the center of your Smart Home System, including:

Lighting Options – Zigbee has an extensive history with lighting, there are far more options for Zigbee based devices than any other Smart Home protocol, including LED bulbs, colour changing LED strips, light switches, dimmer modules and many more.
Lower Power Requirements – up to 10 years battery life.
Optimised For Battery Devices – due to how battery powered devices “sleep” and the extremely low power requirements of Zigbee, it is ideally suited to Smart Devices such as motion sensors, door sensors and water sensors.
Stability – Zigbee is a truly self-healing network, devices will automatically reroute when one device goes offline.
Security – Zigbee uses 128-bit AES encryption, the same type used by online banking services.
Firmware Updates – Over the Air firmware updates (OTA) have always been a key feature for Zigbee, allowing Smart Devices to be updated simply and quickly.
Capacity – Unlike other protocols, Zigbee supports thousands of devices in a single network – up to 65,000! That’s more than enough for even the largest of homes and means you won’t need to have multiple networks to manage.
Affordability – Zigbee devices on the whole are very affordable, often much cheaper than similar devices from other technologies such as Z-Wave and WiFi.

How Does Zigbee Work?

Zigbee is an open standard for a low-cost, low-power, wireless mesh network targeted at the wide development of devices for wireless control and monitoring applications. By building on top of the physical layer and media access control defined in the IEEE standard 802.15.4 it natively supports mesh networking as well as offering secure communications by default.

With Zigbee based devices you get a robust, resilient and self-managing system. Zigbee devices are often much simpler than devices using other protocols such as Z-Wave, preferring to focus on specific tasks such as motion sensing or dimming a light, rather than trying to combine lots of different functionality into one device.

What Do I Need For A Zigbee Network?

For a typical Smart Home System a basic Zigbee network can be formed using just three components:

Zigbee Coordinator (ZC) – This will typically be the Smart Home Controller (sometimes referred to as a hub, gateway or bridge). Its job is to establish the network itself, setup and maintain security, add devices to the network and manage communications between them. There can be only one Coordinator in the Zigbee network and it must be permanently powered.
Zigbee Router (ZR) – Zigbee routers are permanently powered mains devices and these provide the back-bone of the Zigbee network. They direct communications between devices to create a literal route from one device to another. There can be many Routers within the Zigbee network and these are typically Smart Devices such as light bulbs, sockets, plugs, light switches and appliance modules – usually any Zigbee device that is AC mains powered.
Zigbee End Device (ZED) – End Devices are the most basic device on the network, they can only send or receive data, they can’t carry out routing tasks. This means they can only communicate with Zigbee Routers or direct to the Zigbee Coordinator. End Devices are usually battery powered and are typically Smart Devices such as motion sensors, door sensors, temperature sensors and door locks.

Is there a fee for using Zigbee?

No! Zigbee is built into the Smart Home devices that you choose to use already, so there are no fees or additional charges to use them.

Zigbee Compatibility And Interoperability

During the early years Zigbee Smart Devices often used “closed” protocols at the application layer, meaning that products from different vendors wouldn’t interoperate, but fortunately the standard has been through many revisions to improve this.

Broadly speaking there are two Zigbee profiles in use – Zigbee Light Link (ZLL) and Zigbee Home Automation (ZHA). Devices within each profile should work together out-of-the-box and, as long as your Smart Home Controller supports a specific profile, devices from that profile should work within it.

Zigbee also uses a single frequency globally – the 2.4GHz band (the same as 2.4GHz WiFi). This means that you can use devices from around the world in your Zigbee network without having to worry about picking the correct frequency! For further information see the Silicon Labs reference.

There’s also an emerging standard called Zigbee 3.0 which merges both the ZLL and ZHA profiles, combining the strengths of each into one new standard. In most cases Zigbee 3.0 devices are backwards compatible with Zigbee Controllers that only support ZLL or ZHA.

The Zigbee Alliance now promotes Zigbee as the protocol for the so-called “Internet of Things” (IoT) due to its open and non-proprietary nature and because it is now a mature, reliable and clearly defined standard.

What Devices Use Zigbee?

There are thousands of devices from hundreds of different manufacturers using Zigbee so you can be sure that there’s a high likelihood of finding a device to suit most requirements.

Garage door controls, locks, lights, motion sensors, door sensors, smoke detectors, thermostats, remote controls, sirens and appliances are all covered extensively.

Backed by some of the worlds biggest companies, including Philips, Nest, Samsung, Texas, Siemens & Whirlpool, Zigbee technology is currently being built into millions of Smart Home Devices worldwide. Lights, thermostats, alarms, fridges, doors, appliances, utility meters – all are being Zigbee enabled.

Recently the likes of Amazon, Apple and Google have all begun to integrate Zigbee into their Smart Speakers and Smart Screens too!

Is Zigbee Better Than WiFi?

Current domestic WiFi standards are very well suited to high bandwidth tasks such as video streaming, telephony, listening to music and playing games to a handful of client devices such as PCs, laptops, smartphones and tables. Unfortunately they aren’t particularly suitable for situations where there are many, many devices that need to communicate quickly but with much less data.

Most residential WiFi equipment is designed to support a maximum number of client devices – typically between 32 and 64 – so when you add up all the WiFi devices that you already use you may find that you’re already approaching those limits!

That said, WiFi development continues at pace and the latest WiFi 6 standards devices are now available supporting faster speads, improved reliability and increased client density. It’s therefore possible for WiFi Smart Home devices to begin to compete with technologies such as Zigbee and Z-Wave, albeit you’ll need to upgrade your WiFi infrastructure to get those improvements.

Zigbee is designed specifically with this in mind, so is more suited to Smart Home applications.

Is Zigbee Better Than Z-Wave?

Both technologies have their merits but broadly speaking the features and functionality offered by both are similar.

Ultimately there’s no need to choose between them – simply make sure that your Smart Home Controller supports both and you are free to pick and choose from either to suit your requirements!

Do I Need A Hub For Zigbee?

In most cases yes, a Smart Home Controller (sometimes referred to as a hub, gateway or bridge) provides the Zigbee functionality within your Smart Home. It enables you to add and configure devices and to create and run “logic”, sometimes referred to as flows, scenes or moods.

These enable the system to do things automatically, such as turn on lights based on motion detection or raise the heating temperature just before your family arrives home so that your house is nice and warm when they open the front door.

Zigbee devices can be used without a Smart Home Controller for direct / simple one-to-one communication, but this will only give you basic remote control type functionality.

Is Zigbee Secure Or Can It Be Hacked?

As with most technology, nothing is impossible, so anybody that answers this question with a resounding “No” isn’t being honest!

The Zigbee protocol itself utilises AES 128-bit encryption and is built upon the security model defined in the IEEE 802.15.4 standard. Devices in a Zigbee network use two types of security keys to communicate: a network key and a link key.

The network key is shared and used by all devices in the network to securely transfer messages. This key is generated by a “Trust Center”, which in most cases will be the Smart Home Controller. The network key is sent to all new devices joining the network.

Is Zigbee Secure

The network key is never sent to devices unencrypted, instead a default Zigbee standard link key is used to protect the network key when it is being transmitted to joining devices.

Link keys are also used for encrypted communication between devices and are generated and provided by the Trust Center. This provides an added layer of security as it means other devices can’t intercept that communication.

When it comes to securing your Smart Home in general, it’s really a case of implementing best practices in order to mitigate any potential issues. Sticking to industry standard and widely recognised technologies such as Z-Wave and Zigbee, using secure passwords, making sure your WiFi and Ethernet network connections are secure, updating software on Smart devices, hubs and gateways to keep them current – all of these things will help to ensure that your Home Automation system remains healthy, stable and secure.

For further information on the security principles used in Zigbee the documentation is well worth a read.

Can I use Zigbee with Alexa, Google and Siri?

Yes! Some Voice Assistant hardware such as Smart Speakers and Smart Screens support Zigbee devices directly, so you can start to add them immediately. For others you’ll need to use a Smart Home Controller that supports the Zigbee technology and offers integration with your chosen Voice Assistant.

Once set up, you’ll soon be barking orders at your Smart Speaker or Smart Screen!

Can I use Zigbee with Alexa

With natural language recognition and machine learning, you can even make inferences rather than direct commands. Tell Alexa or Siri that it’s too dark and they’ll automatically raise the lighting level accordingly.

Even better, create lighting “Scenes” that can be set automatically – tell Google Assistant “It’s movie night” and sit back as the TV turns on, the AV equipment powers up, the curtains close and the lighting dims down. All without lifting a finger.