In this Article: Design Goals for ZigBee Wireless Communications ZigBee radio network application areas; what devices are included in this network; advantages of ZigBee Radio; smart home control scenarios.
For more than a century, mankind has been using various household electrical appliances, electric light has become familiar and commonplace for us, because electricity is supplied to almost every home today. However, household electrical appliances and devices need to be managed somehow, which forces homeowners to solve not only the problem with the actual construction of a wired power supply system, but also carefully plan the points of placement of switches, control panels for various smart home systems. Moreover, it is not possible to accurately take into account the positions for all the necessary switches, and it is tedious and fraught with costly capital repairs to groove walls under new points. A system based on ZigBee Radio can completely solve this problem and not only it..
Wireless network for smart home
Over the past two decades, wireless communication networks like Bluetooth and wi-fi have become widespread and well known to us. They are suitable for Internet networks, but they are not convenient enough for use in smart home control systems due to the narrow limitations in the number of devices connected to such networks, high power consumption, relatively slow response (for example, for Bluetooth it is 3 seconds) and, importantly, the quality of the connection depends on the design barriers between the on-net devices. Networks built on the ZigBee protocol outperform other network counterparts in all the points described above.
The development of networks based on ZigBee Radio was initiated in 1998 by Philips, after unsuccessful attempts by engineers at a number of leading consumer and medical electronics companies to use Bluetooth and wi-fi in their applications. The ZigBee Alliance, which is developing the corresponding digital radio network, today includes representatives of several hundred global companies interested in this product..
Smart home – application area with ZigBee Radio protocols:
- household appliances intended for the entertainment of households (music and film equipment);
- controllers that control lighting devices, temperature conditions, security equipment;
- alarm controllers responsible for monitoring the consumption of electricity, water, gas, fire protection and smoke systems, managing access to the building, etc..
ZigBee wireless sensor networks are used in both household and industrial areas, the power consumption of their constituent devices is extremely low, which allows the devices to work properly for two years without charging or replacing batteries. The response speed in such networks is 0.015 seconds, i.e. exceeds similar parameters of Bluetooth networks by 200 times.
The devices that make up the ZigBee radio network are divided into three types – coordinator, router and end device.
The coordination device is responsible for the formation of a network tree and communication between other networks, in each ZigBee Radio network there is at least one such device that starts the network. At the same time, the coordinator performs the functions of ensuring network security and configuring the devices connected to it. Its database stores information about the network tree and all devices included in this network – upon discovering a new device, the coordinator determines its admission and synchronizes the network operation taking into account this device.
The router transports data packets between network devices and launches applications. The total number of routers in a given network depends on the number of endpoints served by each of these devices – a maximum of 32 mobile or sleeping nodes can be connected to one router. Since the operation of these devices is associated with the constant sending and receiving of network data, they are connected to a stationary power source.
The end device (mobile or sleeping node) is able to receive and transmit information to only one node (either a router or a coordinator), this device is not engaged in data transfer between devices and is designed to reduce the load on network nodes, which allows them to minimize their power consumption. Basically, end devices are various executive controllers and sensors..
How you can use the ZigBee radio network
One of the popular areas of using wiring products, in which ZigBee technology is applied, is the programming of scenario actions implemented by the smart home control system in response to a certain event. Such an event can be a touch of a certain switch key, a signal from one of the sensors (for example, the level of illumination, smoke, humidity, temperature, movement, etc.) or a timer.
Thus, pressing a single key will be followed by a series of actions that determine the scenario – some groups of lamps will turn off and others will be activated, the roller shutters will change their position, the temperature regime of heating devices, the operating mode of the security system, etc. will change..
Pressing the buttons and turning on the scripts programmed for this pressing is accompanied by light indication near the button – a red LED light means the activation of this scenario, a green one indicates the presence of power supply (switches to red light when the key is pressed). Scenarios can also be controlled remotely – using the remote control or via a GSM channel, from a smartphone.
Of course, it is possible to build the necessary networks and program them for certain scenarios using classical wiring, but this will require tens of meters of cable, many-meter grooves in the walls, a significant amount of work and a lot of time, not to mention the inevitable major repairs. And then – will it be possible to foresee all the future needs of households in the course of such work, because after a while these needs will change, you will want to change something, for example, to supplement the existing system with new network devices, which will mean new major repairs and new expenses?
Meanwhile, radio networks in a smart home will not require laying new power lines and changing the switch placement points – there are solutions for traditional wiring that allow it to be combined with a wireless network, provided that the old switches are replaced with new ones equipped with a radio unit.
Solutions for traditional wiring
The indisputable advantage of networks based on ZigBee Radio is the ability to expand the number of network participants to 65,000 devices, send and receive packets within the network at a speed of 250 Kbps, no need for neutral (grounding), self-recovery and configuration. In case of failure of one of the network devices-routers, the connection between the command and the executive device will not be broken, because each executive device, if necessary, is capable of relaying radio signals of commands through its channels to devices within the network.
The size of the ZigBee radio unit does not exceed 25 mm, therefore, wiring accessories equipped with it can be installed in mounting holes of standard sizes, and the absence of the need for electrical wiring allows you to place such a switch on any surface in the room by sticking to it. And if earlier you had to get up and go to the point where the device was placed in order to change the light intensity, evaluate the visitor at the door, reduce or increase the temperature in the room, etc., then with ZigBee Radio devices this is not necessary – you just need to turn to the device located in any place convenient for household members, for example, near your favorite chair or desktop.
The level of comfort of our houses and apartments consists of many components – some 30-40 years ago the main criteria were the presence of a separate bathroom, garbage chute and gas stove, proximity to the house of a bus stop or metro station. Today, the level of comfort directly depends on good rest after working days, the opportunity to relax without alternating work and household problems with each other. And the systems based on ZigBee Radio are designed for this very purpose..