Zigbee is an open-communication standard that provides a low-cost, low-power alternative to smart-home devices rather than Wi-Fi, Bluetooth, and other wireless protocols. If you thought a true smart home hasn’t arrived yet, Zigbee will immediately correct your perception. On account of its simplicity, standardization, and onboarding support for hundreds of devices/sensors, it will make your home feel smarter in more ways than one.
To explain this, we will not only give a high level overview of this technology but also its look and feel from a user perspective.
What Is Zigbee?
Zigbee can be defined as a communication protocol developed on IEEE standard 802.15.4, which is characterized by extremely low bit rates (20~250 kbps), a large physical range (10 to 100 meters), support for hundreds of end nodes (around 240), and low-latency data transmission (less than 200 milliseconds). Developed and sustained by the Zigbee Alliance, it is currently the most popular standard for IoT device manufacturers, with widespread currency in home automation, healthcare, and industrial IoT.
Formed in 2002, the Zigbee Alliance currently has over 500 leading members. There is also a fascinating story about the name “Zigbee.” It stems from someone observing a “zigzag” dance performed by honeybees while they were returning to their hives. Also, the current logo of Zigbee has a characteristic zigzag shape.
The whole aim of the Zigbee standard is to support extremely low power consumption in the target devices. As a result, it is more useful in control and sensor networks which dominate smart-home end-user devices. In a true smart home, all these devices must work uninterrupted for several years on a single battery. This they do by going into a sleep (or standby) mode while not in use.
The IEEE 802.15.4 radio standard operates in unlicensed bands which varies worldwide. It is 915 MHz in the United States and Australia, 868 MHz in Europe, 784 MHz in China, and 2.4 GHz in the rest of the world.
How Zigbee Works
While there are many complex topologies that can be built around Zigbee networks (Star networks, mesh networks, etc.), a few ideas are common. The following is a simplistic overview which works for a small-scale smart home.
Every Zigbee network has a “Coordinator” or “Bridge” device which connects to the home Wi-Fi router or Mi-Fi via a provided cable, and accordingly, to a mobile app on your smartphone. The coordinator is the root device of the entire network that is commercially available as a bridge product provided by smart home vendors. It can also be fashioned using a Raspberry Pi or other boards.
Sometimes there are intermediate devices called Zigbee routers which act to distribute the traffic. Finally, there are end-user devices or sensors which cannot operate on their own. They will only transmit data to the parent coordinator or router.
Zigbee can have commercial applications as well as find a place in DIY projects of home automation.
Example of Consumer-Grade ZigBee Appliance
Philips Hue lights and other smart home accessories extensively run on the Zigbee standard. They have a commercial Zigbee hub product which connects with various smart-home devices in your network derived from Philips Hue, IKEA, ConBEE Home Assistant, and others.
First, you need to power up the Hue bridge by hooking it up to the Wi-Fi routers via an included cable. For any device connected on the same Wi-Fi network, the connection with the bridge is automatic.
Once the bridge is connected, you will be able to see the active status of the coordinator device. All smart home devices are also visible on the Philip Hue app. You can click on any visible device to manipulate it in your smart home.
We have checked the smart home motion sensor as shown here. You can see a Unique ID assigned by the manufacturer: the “Zigbee ID.” It is a 16 hexidecimal digit (8 byte) string that is unique only to that ZigBee device, assigned by its manufacturer (analogous to the MAC address of a computer).
As shown here, various actions can be coordinated for the sensor, such as starting effect, setting the group color, and brightness. The response is extremely fast due to the low latency of the Zigbee network. Had it been Wi-Fi or Bluetooth, you would have to wait three to five seconds for the connection to be ready. Clearly, you can see the advantage of Zigbee over other wireless networks.
Zigbee Applications in Smart Homes
Owing to its flexibility, extensive range, and connection capabilities with hundreds of devices, Zigbee is a very popular standard for smart homes. From Samsung SmartThings to Wink, Ecobee, and Apple HomeKit devices, almost every set of smart-home devices can be connected to a Zigbee hub.
The advantages of Zigbee in smart homes include:
- Simplicity and affordability: the connections are almost plug and play. There is no delay in onboarding the devices.
- Less failure rate: Zigbee is not that prone to network failures as with Wi-Fi, Bluetooth, or even 5G networks.
- Universal applications: the network can be connected to any device which supports the hub or coordinator/bridge.
- Power savings: you don’t have to worry about power consumption and frequent charging of smart devices in your network.
In summary, a Zigbee-affiliated smart-home network is complete in all respects. With Zigbee, everything you need to do in your home is available on an app now.