Wireless Zigbee technology is one of the main IOT (Internet of Things) communication standards specific for domotics and Building Automation. Thanks to low consumptions and to its high reliability, Zigbee has become one of the major reference protocols in the domotics field, used by major brands and platforms such as Amazon, Google, Apple and many others.
Curated by the ZigBee Alliance (https://zigbeealliance.org/), this standard represents, in reality, a set of communication protocols that acts through the use of low-power and low-consumption digital antennas and has been created to replace other more complex and less economical wireless PANs, such as Bluetooth. The ZigBee Alliance is today made up of a group of manufacturers of communication devices considered inexpensive, very reliable and characterized by interesting energy requirements, as well as by a very low consumption standard.
Created in the late 90s to overcome Bluetooth inadequacy for a certain type of applications, ZigBee operates on 2.4GHz band and is based on IEEE 802.15.4 radio standard. Thanks to two very important features, low power and high reliability, ZigBee has become one of the major reference protocols in the domotics sector, used by great brands and platforms such as Amazon, Google, Apple and many others.
Inside a domestic system there is always an “intelligent” device in charge to coordinate the others, as well as to connect the operation of different accessories, in some cases equipped with intermediate nodes, delegated to transfer data. When ZigBee is present, “smart” objects present in the network communicate each other using the communications trypical of this standard, while people modulate the various activities of the devices through smartphones, PCs or tablets.
In this way, different apps and software are used, but the purpose of this interaction, common to all of them, is to launch immediate and stable connections, with the added value of low consumption.
There are three different types of Zigbee device:
ZigBee Coordinator: it is the “smartest” device; within a network there can only be one, it can operate as a bridge between multiple networks and act also as “deposit” to store security keys.
- ZigBee Router: these devices can also be more than one for each network, they have an interlocutory role, favoring data exchange with other devices.
- ZigBee End Device: they include only the minimum communication functions with the referring node (which can be the Coordinator or also one of the Routers). They require the minimum amount of memory and are therefore cheaper than the other two types of ZigBee devices.
ZigBee standard is designed for applications belonging to integrated systems which require low transmission speed and low consumptions. Its objective is to define a self-managed, performing and reliable mesh communication network, applicable to different uses, first of all domotics. In this application, Zigbee protocoll allows the network to have a reduced expenditure of energy resources; at the same time it will be able to operate for one/two years by using only energy contained in the battery incorporated in the individual nodes. Generally, in facts, the Zigbee protocolls are able to minimize the activity time of the radio transmitter, optimizing and, consequently, also reducing energy consumption.
There are many applications that use Zigbee standard and are used to manage all “smart” devices: therefore, the security systems inside and outside a building, the activation of household appliances, the opening and the closing of curtains and shutters, lighting control and any other activity that can be remotely managed.
even in hotels Zigbee has a useful and innovative multitasking application through a device that allows the management of the entire space, from the temperature control in the different rooms to the detector of open windows, from the access to the rooms to the presence sensor.
ZigBee is a protocol that has been created to satisfy key IoT needs, that are:
- Consume little energy, so as to last for months or even years without the need to replace the battery;
- Remain functional in every environmental condition, which means that its signal is able to cross obstacles as walls and floors without losing efficiency and without interfering with any other wireless networks;
- Offer the possibility to add devices to the network, also to the extent to tens or hundreds of new devices always allowing to all devices to communicate among each other.
Although ZigBee is a “mesh” network the signal comes from the central hub (like in the “star” WiFi network) but unlike what happens in the latter system, all devices connected to Zigbee can operate independently, becuase each of them can act as repeater, transmitting the signal to other devices.
This technical characteristic called Mesh Network makes Zigbee networks particularly flexible, able to cover greater distances and overcoming even important obstacles, all while supporting even thousands of devices connected to the network.
Its main disadvantage is that it is an “open” protocol that can be easily customized. While its extreme comptibility can be considered an added value, on the other hand this factor can cause problems in the uniformity of operation.
Manufacturers, therefore, can modify some aspects in order to make the hubs compatible only with their own devices and consequently causing malfunctions in the overall management of the network.
Zigbee technology allows to intergrate several types of devices as it defines an application protocol for each of them. There are various product categories on the market, including:
- Lighting devices (lighting fixtures, dimmers, pushbuttons, remote controls, etc.)
- Sensors (motion, light, temperature, weather station, ecc.)
- Actuators (controlled sockets, relay modules, HVAC commands, motors, curtains, ecc.)
- Energy meters and other energy management devices
- Safety devices (electronic locks, etc.).
Among the Zigbee devices available on the market we can list some of the best known:
- Amazon Echo Plus, the second generation “smart” speaker, connected to Alexa voice commands. Il can be used to listen to streaming music and is equipped with an integrated Zigbee hub which allows to control several types of home automation devices such as light bulbs, switches, set timers and call anyone who owns an Echo device or the Alexa app.
- Philips Hue, the most famous LED light bulbs in the market: equipped with dimmer adjustment, they are remotely controllable via smartphone.
- Osram Lightify, still on the subject of smart lighting, a huge range of quality products in which you can find not only light bulbs but also sockets, switches and motion sensors, as well as LED strips and chandeliers.
- Ikea Tradfri, a smart remote control which allows the complete control of the lighting system inside and outside the house. Thanks to the ZigBee protocol and the Tradfri app, it can manage up to 10 LED light sources.