Advantages of ZigBee over Wi-Fi
What is Wi-Fi?
Wi-Fi is a family of wireless network protocols, based on the IEEE 802.11 family of standards, which are commonly used for local area networking of devices and Internet access. Wi‑Fi is a trademark of the non-profit Wi-Fi Alliance, which restricts the use of the term Wi-Fi Certified to products that successfully complete interoperability certification testing. IEEE expanded the original 802.11, creating IEEE 802.11b/g/n that supports bandwidth upto 11 Mbps/54Mbps/300Mbps, and uses the unregulated radio signalling frequency - 2.4GHz.
The bandwidth of Wi-Fi is high making it perfect for activities like streaming music or checking email on a phone or tablet. But for smart home automation, the disadvantages of Wi-Fi are:
1. It only works well for short ranges from the single central Wi-Fi hub or router. If your smart devices are too far apart you will have to use an extender, which will likely affect latency and connection speed.
2. It’s not very power-efficient. WiFi-based devices usually last about 10 hours making them unsuitable for battery operated sensors.
What is Zigbee?
ZigBee is a worldwide standard for low power, self-healing, mesh networks offering a complete and interoperable IoT solution for home and building automation. The origin of the ZIGBEE” name can be traced to the waggle dance of honey bees after their return to the beehive. ZigBee is the primary networking protocol based on 802.15. 4 radios.
A mesh topology is a type of networking where all the nodes cooperatively distribute data. ZigBee networks can support hundreds of nodes, and have enhanced security features. See an example of the Zigbee mesh network topology in the figure below.
The ZigBee® Alliance, a non-profit association of organizations creating open, global standards that define the Internet of Things for use in consumer, commercial and industrial applications, unified its market-leading wireless standards to a single standard named ZigBee 3.0. This standard provides interoperability among the widest range of smart devices and gives consumers and businesses access to innovative products and services that will work together seamlessly to enhance everyday life.
Advantages Of A Mesh Topology
One of the advantages of a mesh topology is that (in theory) you don’t need to add routers to the network, as each node can act as a router. If you’re working on a mesh network for the lighting in your office building, and you want to add a light in a particular room, you should be able to add the light and have it automatically connect to the network. There isn’t a lot of extra management that needs to happen, which makes the network scalable.
Another benefit of a mesh network topology is that if one of the nodes goes down, it doesn’t necessarily bring the entire network down. The network can heal itself around a bad node if other nodes can complete the mesh. Additionally, if you need to get more range out of a mesh system, you can add another node and the messages can hop through the mesh back to the gateway—which is why some believe mesh networks are more robust.
Because all nodes in a mesh are receiving and translating information, there is some redundancy in a mesh topology; however, you can also gain speed with the excess bandwidth. If one route happens to be slow, a mesh network could potentially find a better route and optimize itself.
Zigbee is a mesh network. It means that signals can easily hop from one device to another one without each standalone device connecting to Wi-Fi. It generally requires a central hub to connect to the network. Furthermore, this protocol standard operate on the same AES-128 symmetric encryption offered by online banks, no need to worry about safe communications.
Zigbee is open-source software. Based on Institute of Electrical and Electronics Engineers (IEEE) standard which develops a personal area network radio standard – 802.15.4. There are no limitations to the amount of “hops” between devices. Plus, the data rates of Zigbee is 40-250kbps. Comes with a transmission range up to 100 feet (30m).
Recently, SONOFF has launched a more compact ZigBee Smart Switch - ZBMINI that connects to SmartThings hub to control all the connected appliances via SmartThing APP on iOS/Android phones to access rooms, scenes, members or automations mode to build a smart house. Seamlessly works with Amazon Alexa platforms including ZE39KL Echo Plus, DW84JL 2nd Gen Echo Show & L9D29R 2nd Gen Echo Plus.
Zigbee runs on the 2.4GHz frequency with rapid transfer rates, which is comparable to a frequency for Wi-Fi. Also operates on the 915MHz bands in the US.
3. ZigBee Battery Life
ZigBee’s best quality is its low power-consumption rate and battery life. Its protocol was designed as “assemble and forget”, meaning once you set it up, it can last for months. Supports battery-operated devices. Some devices can run up to 7 years on one set of batteries or devices that don’t require batteries, like light switches. Due to its energy-saving features, Zigbee is an absolutely solid choice for those using smart sensors, smart locks and other smart devices that require battery power. But, Zigbee devices using different protocols can’t communicate with each other quite well. ZigBee 3.0 changes all this and provides interoperability among the widest range of smart devices that work together seamlessly to enhance everyday life.
4.0 Support Brands & Devices
Zigbee can work with up to more than 6500 devices. Below are some known as brands and devices which support Zigbee protocol.
Compatible with Zigbee:
Amazon Echo Plus (support Alexa for voice control )
Philips Hue (Signify)
Yale smart locks
ADT Security Hub, etc.
5.0 SONOFF ZigBee Bridge
SONOFF ZigBee Bridge is the low cost Wi-Fi to ZigBee bridge or hub or ZigBee Co-ordinator that is a heart of a smart home. Much cheaper than Amazon Echo Plus. It enables you to remotely manage a variety of ZigBee devices and sensors for monitoring and control purposes of home, and allows you to create smart scenes to make Wi-Fi and ZigBee smart devices communicate to access a smarter home and control them all using the eWeLink APP. It maximizes efficiency for up to 32 connected sub-devices which are ZigBee-based switches, plugs and security sensors. SONOFF BASICZBR3 Wi-Fi Smart Switch, SONOFF SNZB-01 Wireless Switch and sensors like SNZB-02 Temperature and Humidity Sensor, SNZB-03 Motion Sensor and SNZB-04 Wireless Door/Window Sensor can be connected with the Bridge to give you the possibility to create various scene linkages. As for more supported devices, the Bridge also can work with one-gang smart switch, temperature and humidity sensor, motion, wireless door/window sensor and water sensor that are certified by ZigBee Alliance. It supports to add a camera on the Bridge or sub-devices, convenient to view your home on any one of them. Can also command Alexa or Google Home to voice control your home
ZigBee specifies three different device types: the ZigBee Coordinator (ZC), the ZigBee Router (ZR), and the ZigBee End Device (ZED). These three devices play different roles in a ZigBee network. The key difference between these is that an end device (ZED) can not route traffic, routers (ZR) can route traffic, and the coordinator (ZC), in addition to routing traffic, is responsible for forming the network in the first place.
A ZigBee network has exactly one ZC device. The ZC coordinates the actions of the network as a whole and is responsible for bootstrapping the network. The ZRs build a network between themselves through which packets are exchanged. The ZEDs are logically attached to a ZR. ZEDs communicate only with their ZR, but cannot communicate between each other.
Each of the ZigBee device types has been designed for a specific deployment. ZCs and ZRs have a higher power requirement than ZEDs and cannot be battery-powered. The ZED has a lower power requirement and achieves a long lifetime on batteries. As per IEEE 802.15.4, ZC and ZR are fully functional devices (FFDs), whereas the ZEDs are reduced function devices (RFDs).
The ZC is responsible for bootstrapping the network. During the bootstrapping process, the ZC chooses the personal area network (PAN) identifier that will be used by the network, as well as the physical radio channel on which the network will operate. It stores information about the network, including acting as the trust center and repository for security keys. After bootstrapping, the ZC acts as a normal ZR device.
ZEDs are off most of the time, thus they are not able to receive any traffic sent to them. Instead, they periodically wake up and check for messages at the ZR with which they are associated. The ZR buffers data sent to their ZED nodes and sends these data whenever they get a poll request from a ZED. The ZED transmits data to the ZR at any time, since the ZR is always awake. The wake-up schedule for ZED is defined by the application developer, not by the ZigBee specification.