There's been an explosion in smart home devices over the past few years. What was once referred to as "home automation" and still referred to as "Internet of Things" has now settled into a more friendly category we call smart home. We've got heating, lighting, cameras, sensors for just about everything, as well as new devices popping up every week to drag your home into a connected future. 

Over the past few years, we've moved from a position of disconnected systems into a world with emerging hubs, with big devices like the Amazon Echo and Google Home acting as hubs to tie all your connected services together, along with emerging platforms like Apple HomeKit and Samsung SmartThings.

So what role does ZigBee have to play in this brave new world of the smart home? Pocket-lint is here to supply all the answers.

The whole idea behind the smart home it to have everything talking to everything, so you stay informed while you're devices stay informed too. That might be that your lighting talks to your security camera or that your smart coffee machine turns on when you get out of bed. The Internet of Things might be a fairly useless term, but essentially, that's what's happening - everything is connected, meaning that information can be shared and your life can be controlled without the need to visit each thing individually.

All of these connected devices are being handled by automatic systems over a single network. The result? You have a smart home, thanks to smart applications and devices. But there's just one problem: many companies make different devices. In order to get them to work together on a single network, you have to use a single common language. That's where ZigBee comes in.

ZigBee is based on the IEEE's 802.15.4 personal-area network standard. All you need to know is that ZigBee is a specification that's been around for more than a decade, and it's widely considered an alternative to Wi-Fi and Bluetooth for some applications including low-powered devices that don't require a lot of bandwidth - like your smart home sensors.

ZigBee is for sensor-monitoring and control of various applications/devices from multiple companies, because it lets ZigBee-enabled devices work and operate together while also giving you the ability to control them. Hence why it is ideal for smart homes.

A typical example is when you own a smart light bulb (that is ZigBee-enabled) and a smart light switch (that is also ZigBee-enabled), and you want the light switch to communicate with and control the light bulb. With ZigBee, the two devices - even if they're from different manufacturers - speak a common language.

ZigBee does not focus on the point-to-point market, such as Bluetooth, where one high-powered device sends data to another high-powered device over a short range. It's also not for standard wireless uses like when you would stream audio or movies.

You should only use ZigBee if you need to send data across a large area, where it traverses multiple hops, and all the devices you want to control are low-powered or even battery-powered. For this reason, ZigBee is most used in industrial and smart home systems (such as a wireless light switch for a lighting setup).

Keep in mind that while ZigBee's network layer supports both star and tree typical networks, it's often associated with a mesh network.

In reality, for a customer putting together a smart home, a device that supports the ZigBee protocol may still be siloed, but as we move forward, with more devices wanting to act as the central controller, having fewer wireless protocols for your smart devices might be a distinct advantage - especially if it means you can avoid having a huge collection of hubs connected to your router.

A mesh network is when a network connection is spread out among wireless nodes that can communicate with each other and share a network connection across a large area. Think of nodes as small radio transmitters that function in the same way as a wireless router. ZigBee's ability to support mesh networking means it can boost data transmission range and provide greater stability (even when a single connected node fails and doesn't work).

ZigBee nodes can be coordinators, routers, and end devices. Coordinators establish the network and store information like security keys, while routers act as intermediate nodes and relay data from other devices. And finally, end devices are low-power gadgets that can communicate with coordinators and routers but cannot transmit data to other end devices.

In other words, with ZigBee, you will likely have a master coordinator node that controls other connected nodes. If one node fails for some reason and cannot communicate with a second node on the mesh network, the master node and second node may communicate by linking to a third node within range. Every node acts as a repeater of sorts, and all nodes cooperate in the distribution of data in the mesh network.

ZigBee supports up to 65,000 nodes on a single network.

Putting this into simple terms, unlike Wi-Fi or Bluetooth, in a mesh network the device doesn't need to connect to the source hub directly, so it steps around the problem of range. Because each device will talk to the others in its mesh, you can string your mesh over a greater difference without the worry of devices not being able to communicate.

The ZigBee Alliance was established in 2002. It's a consortium of companies and other organisations that support the development of ZigBee and promote its use. It also performs interoperability testing, certifies products, and maintains the IEEE 802.15.4 standard.

There are more than 400 Alliance members and 600 certified products. Members include promoters (such as Philips and Texas Instruments), participants (such as Belkin and AT&T), and adopters (such as Logitech and Motorola Mobility).

Promoters have representation on the Alliance's Board of Directors and hold voting rights. Participants hold voting rights too but play a more active role in evolving ZigBee and receive early access to specifications for development. Adopters are members that receive access to completed ZigBee specifications and standards.

So now you know what ZigBee is, it's worth running through devices that work with ZigBee. Just because they use this standard of wireless networking doesn't immediately mean that things will work in harmony, afterall, you might not have a controlling application that knows what all these devices are.

Here are some of the big users of ZigBee in the smart home:

  • Comcast
  • Honeywell
  • Huawei
  • Philips
  • SmartThings
  • Texas Instruments
  • Amazon
  • Belkin
  • Ikea
  • Lutron
  • Nokia
  • Osram
  • Bosch
  • Indesit
  • Samsung
  • Velux
  • Humax
  • Panasonic
  • Miele

Just because a company uses the protocol, doesn't mean it will instantly play nice, however. Philips Hue uses ZigBee to connect its bulbs, but that doesn't always mean you can add in additional bulbs from a different manufacturer.

However, with the announcement of the Amazon Echo Plus, there's likely to be a big change in how people relate to ZigBee. The new Amazon Echo Plus will be a smart home controller using ZigBee to connect directly to compatible devices, such as Philips Hue lightbulbs.

Yes. There are many alternatives to ZigBee that target the same general applications. Some alternatives are more versatile and be configured for any kind of short-range wireless task, while others are more complex and require longer development times. One of the more notable alternatives is Z-Wave.

Z-Wave has an alliance, just like ZigBee. The Z-Wave Alliance is a consortium of more than 250 manufacturers that build wireless home control products based on the Z-Wave standard. There are more than 900 different products certified by the Z-Wave Alliance, though that number is constantly growing.

There's also another scenario that's tied together smart home devices in recent years. The emergence of Amazon Alexa, Google Home and Apple HomeKit has put in place a controller that is compatible with different systems. While ZigBee devices will notionally understand the wireless protocol that different devices might be using, it's really the open platforms that's currently tying things together. For example, you can enable combinations of products to work together by grouping them with Amazon Alexa, which then pushed out the commands to all the devices, via the cloud.

In theory, a central ZigBee controller could communicate directly to devices if it was setup to do so, cutting out the cloud requirement and working on the local network instead.