He comes across a new word for himself - Zigbee. This logo is often found on packaging various devices for a smart home, for example it can be found on products Xiaomi Smart Home, on Philips Hue and IKEA TRÅDFRI light bulbs.

Zigbee logo on the packaging of a set of smart light bulbs

At the same time, complete with such light bulbs, the manufacturer also sells a device called a “bridge” or “hub”, which is necessary for the full operation of the smart lighting system. In this article, we will tell you in detail about what Zigbee is and why this standard is increasingly used in smart home systems.

What is Zigbee

Zigbee is a wireless communication standard similar to Wi-Fi and Bluetooth, but created specifically for the Internet of Things and . Thanks to the ZigBee protocol, devices in a smart home “communicate” with each other.

Zigbee is designed specifically for the Internet of Things and the smart home.

Wireless standards that existed 15 years ago, such as WiFi and Bluetooth, were not suitable for new emerging needs, such as smart House. These standards were not reliable enough, and their modules were too expensive. To develop new network protocol An association of leading technology companies (Philips, Samsung, LG, Siemens and others) called the Zigbee Alliance was created. And in 2004, an international standard was adopted regulating the new Zigbee protocol, operating at frequencies that do not require special permission.

The name Zigbee comes from the words “zigzag” and “bee”; in the West, the term “zigbee” refers to the dance of honey bees. This name, according to the developers of the standard, emphasizes that the Zigbee network has a mesh topology (structure) and, thanks to special routing algorithms, is reliable and capable of self-healing in the event of loss of communication between individual nodes. At the same time, equipment for Zigbee is compact and low cost.

Difference between Zigbee, Wi-Fi and Bluetooth

The Wi-Fi and Zigbee standards are similar in some characteristics:

• Both operate at a frequency of 2.4 GHz, which does not require special permissions when used
• Both protocols have a range of up to 20 meters

But Zigbee has key differences that make this standard much more suitable for communication between smart home devices.

In a Zigbee network, there is a direct connection between nodes, and not just a connection to the “center”.

Topology. The main difference between Zigbee and Wi-Fi is the use of a mesh topology, rather than a star topology, where all network nodes are connected through a central router. In a “star” structure, if the connection to the router is lost, the node cannot communicate with the rest of the network participants. For example, if your computer disconnects from the router, you will not be able to transfer a photo from your tablet to it - Wi-Fi does not allow direct connection between devices on the network.

In a Wi-Fi network, devices can communicate with each other only through a central node - a router.

But thanks to the cellular structure, if one connection is broken, a bypass route will be laid out, and the signal will reach the recipient along a new path. This is possible due to the fact that there is a direct connection between the nodes, and not just a connection with the “center”. This topology is much more reliable and is used, for example, on the Internet itself.

In a Zigbee network, devices can communicate with each other directly

Specific example. The water leak sensor, connected via Wi-Fi, is located at a great distance from the Wi-Fi router and there are 2 concrete walls between them. At the time of an accident, the sensor may simply not transmit a signal about a leak due to a weak Wi-Fi signal. The router will not receive a signal that the sensor is triggered, will not transmit this signal to the control center, the control center will not close the valve, and flooding will occur. But if your smart home worked on Zigbee, then with a weak direct connection between the sensor and the control center, the signal would not be transmitted directly, but through other devices: a light bulb in the corridor, a switch in the room or smart plug. That is, other devices would act as intermediate stations when transmitting a signal about a leak to the smart home controller and a return signal about closing the valve.

Energy consumption. Very low power consumption of Zigbee modules is achieved due to a special “sleep” mode when the device is not in use, and low data transmission capacity (250 Kbps versus 300-1000 Mbps for Wi-Fi). High throughput Zigbee is not needed, because you need to transfer very small amounts of data from sensors and electrical appliances, but Wi-Fi should provide real-time video viewing, etc. As a result, the Zigbee module can operate for several months on a simple battery.

Speed. Before the advent of Zigbee, smart home systems tried to use Bluetooth. The range of these protocols is approximately the same, but Bluetooth has too long delays. The delay in signal transmission for the Bluetooth module is several seconds versus 30 milliseconds for the Zigbee module! 30ms is much less than the reaction speed of a person - for us, turning on and off a Zigbee light bulb happens instantly.

Number of nodes. Wi-Fi is simply not designed to connect a large number of participants to the network. In theory to one Wi-Fi router It is possible to connect several hundred devices, but every active user knows that this is not achievable in practice. Average routers price category start to freeze and require a reboot after connecting 15-20 gadgets: laptops, smartphones, tablets and other devices of your family. But one Zigbee network can have thousands of nodes and still work stably. Ability to function reliably large quantities connected devices is a necessary characteristic of a network for a smart home and the Internet of things.

Devices with a Zigbee module are much cheaper than those with Wi-Fi.

Price. For manufacturers, a zigbee module costs less than Wi-Fi. Smart home devices with Zigbee connectivity are also significantly cheaper than similar devices with Wi-Fi. Example: an IKEA Trådfri zigbee light bulb with adjustable brightness costs about 700 rubles, and a similar product, a TP-Link LB110 wifi light bulb, costs 2,300 rubles.

Smart home and Zigbee

Zigbee networks are used in industrial automation, commercial real estate, and medical equipment. But by far the most widespread and popular application of Zigbee is .

Before Apple, Google and Amazon entered the smart home market, the Z-Wave standard was popular for some time. This protocol was a competitor to Zigbee, but it is closed, and manufacturers of smart home devices must buy the Z-Wave module from a European manufacturer. Zigbee is an open standard, and any company can produce its modules according to an open specification. Therefore, Zigbee devices are cheaper than devices with Z-Wave, and now we can definitely say that the Zigbee protocol has won and has become the de facto standard for smart home systems. ZigBee is used by all major companies in the smart home market: Amazon, Philips, Samsung, Xiaomi, LG, Logitech, IKEA and many others.

Ikea Trodfrey smart light bulbs work via Zigbee

The presence of a Zigbee module does not make devices from different brands compatible.

There are every electrical appliance with Zigbee on sale that you can imagine: light bulbs, switches, sockets; motion, leak and smoke sensors, door and window opening sensors; air conditioners, thermostats, cameras and much more. But it should be noted that the mere presence of a Zigbee module does not make devices from different manufacturers compatible with each other (just as in smart home devices with Wi-Fi module). For example, the Ikea Trodfrey zigbee bulb will not work with the Xiaomi Smart Home Gateway zigbee hub. But some companies are adding support specific devices from other manufacturers, for example, the same light bulbs from Ikea will work together with the Philips Hue Bridge.

Therefore, when choosing Zigbee devices for a smart home, you need to choose a high-quality manufacturer that you trust, because you can only connect their products to its bridge. You also need to make sure that the bridge of this brand supports integration with modern platforms: Apple HomeKit, Google Assistant or Alexa (about this).

Hub for smart home – Zigbee bridge

A modern smart home cannot be imagined without the ability remote control. For example: open a mobile application on your iPhone or Android and turn on the air conditioner in the living room when returning from work, or check whether you unplugged the iron from the outlet while in a taxi taking you to the airport, and if you still forgot, unplug the outlet.

For remote control, including from a mobile application on Android or iOS, the network of Zigbee devices must be connected to the Internet, and this is why network bridges (Bridge, as Apple and Philips call them), also known as smart hubs, are used Hub, as Google, Amazon and Samsung call them). Another name for devices of this type is Gateway, a name used by IKEA and Xiaomi.

A network bridge is a coordinator in a Zigbee network, and unlike end devices (for example, battery-powered door sensors), it must always be connected to electricity, since the coordinator in a Zigbee network never sleeps. To communicate with your home network and the Internet, the hub is connected via a regular twisted pair cable to your Wi-Fi router (a wired connection is the most reliable).

A network bridge connects the wireless Zigbee network of a smart home with the Internet

As you can see in the picture, the hub literally works as a bridge between smart home devices and the Internet. It allows you to connect to your home from anywhere in the world, monitor its status and control all devices. To connect to a smart home, a mobile application or voice assistant is used (more on this below).

A line of Zigbee smart home devices from a specific manufacturer also has a bridge of the same brand, to which the devices are connected. At the same time, as a rule, Zigbee devices from other brands will be incompatible with a “foreign” bridge, and in order to add devices from a new manufacturer to your smart home system, you will need to buy another hub, “native” for the new manufacturer.

List of the most popular Zigbee hubs/bridges/gateways:

• Philips Hue Bridge
• IKEA TRÅDFRI Gateway
• Samsung SmartThings Hub
• Xiaomi Smart Home Gateway (buy on Aliexpress)

Siri, Google Assistant, Alexa and Zigbee

A modern hub provides the opportunity voice control smart home through a voice assistant. Likewise, if you want to control it with Assistant on your Android phone or , look for the “Works with the Google Assistant” logo.


Well, if you have a speaker and your favorite virtual assistant is Alexa, then you need bridges with the “Works with Amazon Alexa” logo.

Be very careful, some hubs provide integration with all of them at once voice assistants, such as Philips Hue Bridge, while others only support one assistant. For example, the widely loved and very low priced Xiaomi Smart Home Gateway only works with Alexa (the Xiaomi kit can be bought on Aliexpress). That is, you will not be able to control a smart home built on a Zigbee hub from Xiaomi in Russian, since Alexa (unlike Siri and Google Assistant) only works in English and German.

We hope that our article helped you understand the differences between Zigbee and Wi-Fi, and now you understand why Zigbee is so widely used in smart home systems, and why it is needed network bridge. We will be glad if you share this article on in social networks. You can also subscribe to our Youtube channel or and receive new articles about home automation and voice assistants.

Hello, dear readers and guests of the Electrician's Notes website.

In my previous publications, I introduced you to touchscreens, controlled both manually and from the control panel.

But today I would like to draw your attention to the Sonoff relay (switch) Basic version with the ability to control directly from mobile phone via a Wi-Fi network or the Internet.

The Sonoff Basic relay is a small device (88x38x23 mm), which can be easily placed behind the ceiling space, in a building niche, or in the bowl of a chandelier or lamp.

Its cost at the time of publication of the article is slightly less than 300 rubles. As you understand, this is quite reasonable money, and for such a modern device. I bought it from a well-known trading platform AliExpress (link will be at the end of the article).

The kit included two protective covers with mounting screws, but, unfortunately, there were no instructions.

The Sonoff relay has the following specifications, some of which are displayed directly on its body:

• maximum controlled load current 10 (A)
• supply voltage from 90 (V) to 250 (V)
• wireless standard 802.11 b/g/n
• security protocol WPA-PSK/WPA2-PSK
• operating temperature from 0°С to 40°С
• weight about 50 g

Sonoff Basic relay capabilities:

• load management via Wi-Fi
• Internet load management
• load control according to a given timer, both with direct and countdown
• load management from multiple mobile phones

These are the capabilities of the Sonoff relay. It can be safely used in smart home systems and for other various needs and requirements.

First, I will tell you how to connect Sonoff, and then we will check all its declared control methods in practice.

So, let's go.

Installation and connection of Sonoff relay

For the Sonoff relay to operate, it needs a supply voltage of 220 (V), which means it can be installed without any problems in a place convenient for you, for example, in the bowl of a chandelier or directly under a suspended ceiling, as well as directly in the junction box if there is enough space there.

To attach the relay to the surface, it has two mounting holes.

The connection diagram for the Sonoff relay is very simple.

The phase and zero of the 220 (V) supply voltage are connected to the terminals (L) and (N) on the (Input) side, respectively. Naturally, when connecting, do not forget about .

Please note that the connected conductors must have a cross-section of no more than 1.5 sq. mm. But I still tried to connect wires with a cross-section of 2.5 sq. mm. As a result, a rigid (single-wire) wire can still be connected without problems, but a flexible (multi-wire) wire can be inserted into the terminal with great difficulty, so it even had to be slightly flattened and deformed.

For example, I used a power cable of the PVA brand, which just has a cross-section of 2.5 sq. mm. At the other end of the cable there is a plug, which I will later connect to any socket with a voltage of 220 (V).

The load phase and zero are connected to terminals (L) and (N) on the (Output) side, respectively.

To make it easier to connect the load, I connected a socket to the relay output.

By the way, terminal covers not only have a protective function, but also act as clamps for power wires or cables.

This is how everything turns out beautifully and neatly. Sonoff relay connected.

As a load I connected LED lamp, about in one of his articles.

Here is a simple example of a Sonoff relay wiring diagram for a group of lamps.

By the way, it is not necessary to use only a lamp or a group of lamps as a load. You can safely connect any other load to the output terminals, not exceeding the rated current of 10 (A). And if you still need to control a load with a current value above 10 (A), then you can connect it to a contactor, and use a relay to control the coil of this contactor.

In this regard, we can add that when using a contactor, you can control at least a single-phase load, at least three-phase, at least alternating current, even direct current.

It will look something like this.

Thus, the scope of application of Sonoff relays is very wide and varied. It can control at least one light bulb, a powerful single-phase electric heater, a three-phase electric motor, etc. It all depends on your needs and requirements.

Now let’s look at all the possibilities for controlling the Sonoff relay in more detail.

I will not open the relay and look at its structure; there is already plenty of information on this matter on the Internet - look at the relevant resources on electronics. And judging by the reviews, the performance of the relay is quite decent. By the way, for those interested in knowing, the relay is assembled on the basis of the famous Chinese microcontroller ESP8266.

Load management via phone via Wi-Fi network

Before I talk about controlling the relay via Wi-Fi, I will say that it can also be controlled manually. To do this, there is a small recessed black button on its body. So, when you press it briefly, the relay turns on, and when you press it again, it turns off. Moreover, for this it is not necessary that the relay be connected to a Wi-Fi network - control will also be carried out in Offline mode.

But besides this, the button also contains other functionality, which I will discuss below.

To implement the ability to manage load via Wi-Fi and the Internet, you need to install the eWeLink mobile application on your phone. This application can be found for both Android and iOS devices. To make it easier to find the application, you can use the necessary QR codes on the packaging.

For Android devices, the eWeLink app can be downloaded for free from Google Play and install it on your phone without any problems. The program interface supports Russian.

For iOS devices this application available in App Store. I have not tried to download and install this application on an iPhone or iPad, so if you have tried this application on iOS devices, please post your results in the comments.

After installing the eWeLink application, you will need to immediately register by indicating your country and your email address. In this case, the phone must be connected to the Internet.

After this, a verification code will be sent to your email (valid for 30 minutes), which must be entered in the appropriate “Email code” line. On the same page you must enter a password to log into your future account (at least 8 characters).

By the way, letters reach the mail services Mail.ru and Mail.yandex.ru (Yandex mail) without problems. But as far as I know, Post service Gmail.ru (Google mail) letters with a verification code are not always received, so please take this into account.

Then you need to pair the relay and router by long-pressing (for 5 seconds) the same button on the switch body, after which the green LED on the relay will blink. Check the box for the first connection mode and click “Next”.

Now you need to select our Wi-Fi network from the list and enter its password. To avoid having to enter a password every time, you can check the “Remember password” checkbox. Click “Next”, after which the search for our device and its registration will begin (it took me no more than 2-3 minutes).

After successful pairing, the relay automatically transmits data to the Chinese cloud (Amazon AWS or Coolkit), which makes it possible to control it via the Internet. But I will return to this a little later.

As you can see, our relay is now displayed in the list of all devices (for now it is the only one in the list, but others will appear in the very near future).

When the relay is online, the green LED on its body is always lit. As soon as the LED starts blinking, it means the connection with the router or the Internet is lost. It is precisely by this indicator that it is convenient to determine whether the relay is online (Online) or not (Offline).

While I was testing this device, I did not notice any problems with network loss. The device is always online and responds stably to control commands.

Now you can try to turn on the relay via your phone. To do this, click on “Relay 1”. A red message immediately appeared indicating that it is necessary to update the eWeLink application, although the update is not displayed on Google Play.

We go to the device settings (three dots in the right corner) and see that the application has a current version of 1.5.2, and more is available a new version 1.5.5. Click on the “Download” icon and the application update begins. After the update, the red inscription disappears, and in the settings we can see a new one current version 1.5.5.

Remember!!! The main condition for the relay to work is the availability of Internet access.

If Internet access suddenly disappears, the green LED on the relay body will start blinking, and the application will display Offline mode on its tab, i.e. not available for management.

So, to turn on our “Relay 1”, you need to enter it and click on the round virtual button in the center of the screen. Moreover, you can control the relay from the general list of all devices by clicking on the corresponding small button (on the left). In general, whatever you like.

When the relay is in the off position, the button is white with a gray background around it. When the relay is turned on, the button changes its color to green, and the background around it becomes blue.

In addition to the banal principles of control, you can set the time for turning the relay on or off using a timer by setting the appropriate date and time for its control.

What was surprising was that the relay operates according to a given timer even when it is offline, which means that all specified timer programs are stored directly in the relay’s memory.

Click on the “Add timer” button and go to the timers settings page. Each timer is configured to either turn the relay on or turn it off. There are two options for setting the timer:

• one-time (one-time triggering on a given date and time)
• repeated (periodic triggering on a given date and time, including indicating specific days of the week)

In addition to the countdown timer, there is a countdown timer. Very necessary functionality for certain purposes. It is configured similarly to a direct timer, only with the possibility of a single operation.

In addition to the forward and reverse timers, there is a cyclic timer in the “Settings” tab (three dots in the right corner).

In this tab you can configure various options for relay operation cycles. I won’t talk about this in detail, because... Everything here is simple and intuitive.

The total number of configured timers, including the cyclic timer, can be no more than 8. And be careful, because when different timers overlap each other, none of them may work!!!

Also in the settings you can specify in what position the relay will remain if the 220 (V) power supply is suddenly turned off. There are three options here. By checking the appropriate boxes, you can choose that when the 220 (V) power supply reappears, the relay can either turn on, turn off, or remain in its original state.

By the way, this is a very convenient feature. Just remember about the nuance that, when the 220 (V) power disappears and reappears, for some reason it always turns on, even when it is in the original state off. Imagine that you are not at home, the voltage in the network “blinked” a little and the controller independently turned on the chandelier. Such an incident will not happen here, because... in this case, everything can be customized to suit your needs.

In addition to the above, all your connected devices in the eWeLink application can be grouped together and combined in various scenarios.

Is it possible to control the relay from several phones at once?

Can! Naturally, in this case, you need to install the eWeLink application on each phone.

There are two options here. The first option is to log into the eWeLink application using the same name and password with different phones and control the relay.

The truth is, if you log into the application on one phone, and then at the same time log into the application using the same username and password, but on another phone, then an error will occur on the first phone and the application will automatically exit. In this case, the second phone remains in the application and can be used to control devices.

At the same time, I would like to note that when controlling a relay from one phone, its status is displayed almost instantly on all phones that are connected to it.

Load management via the Internet

In addition to controlling the relay via your phone via a Wi-Fi network, it can also be controlled via the Internet from anywhere in your location, i.e. absolutely from anywhere in the world where there is Internet access.

So, to control the switch via the Internet, you need to log into the same eWeLink application using your name and password that you specified during registration. And then everything is by analogy. It’s the same application, the same settings, the same control buttons, etc., the only difference is that you are not at home within the coverage area of ​​your Wi-Fi networks, and at a distance of hundreds and thousands of kilometers from home.

A little about the cloud.

But still, you will not be able to control the relay without the Internet, because... control does not go through local network, and via the Internet, i.e. the same Chinese cloud that I mentioned above. And it doesn’t matter whether control is via Wi-Fi or the Internet, control access is always via the cloud, and to access the cloud you need Internet access.

In this regard, various craftsmen have already figured out how to untie this device from the Chinese cloud or make control only through a local home network. For those interested, then this information can be found on certain resources.

By the way, if you need a similar device, but with additional function radio control from the remote control, you can order a Sonoff relay of the RF version.

If you want to control the load where there is no Internet network at all, then you can use the Sonoff version G1 relay (GSM/GPRS with SIM card support). This manufacturer also has relays with temperature and humidity sensors Sonoff TN10/TN16 and two-channel (for controlling two independent loads) relays Sonoff Dual.

In general, the manufacturer Sonoff has many different devices, I will tell you about some of the most interesting and significant ones on the pages of my website, so subscribe to the newsletter so as not to miss interesting releases.

You can buy a Sonoff relay here:

1. Sonoff Basic: https://goo.gl/jXyNm3
2. Sonoff RF (with radio control): https://goo.gl/TRPqN6
3. Sonoff G1(GSM/GPRS with SIM card support): https://goo.gl/EkpTdp
4. Sonoff TN10/TN16 (temperature and humidity sensor): https://goo.gl/MWAL5p
5. Sonoff Dual (two-channel): https://goo.gl/a7rV56

And by tradition, a video based on the article, where you can more clearly see the configuration and control of the Sonoff relay:

The Chinese corporation ITEAD has released an incredibly simple and at the same time functional device for remote control of any electrical load via the Internet. In fact, this is a wifi relay built on the well-known ESP8266 chip and working through its own cloud service. The most amazing thing about this device is the price - you can now order the device on the manufacturer’s website for only $4.85. Perhaps this is the simplest and most affordable way to automate a country house.

The built-in relay allows you to control a load of up to 10A, and at high currents no one bothers to install an additional solid-state relay or contactor. The scope of application is limited only by your imagination. I installed such devices to control street lights in a country house and to turn on various electrical devices (for example, to turn on a garden pump). Remote control possible from anywhere on our planet where there is Internet access.

2. The device has two contact groups: for connecting to a 220 volt network and a terminal for connecting a load. The board itself contains a transformer for powering the electronics, a 3.3-volt voltage regulator, a power relay, pins for an additional 433 MHz radio module, GPIO pins and an ESP8266 module (on the back of the board). Among the controls, there is one non-locking button, which is used either for local control of turning on/off the load, or for activating the programming mode. The operating mode is indicated on a nearby LED.

3. The assembly is quite neat, although the flux on the power tracks is poorly washed off. But there are cutouts between the power lines and we can quite confidently say that the device will withstand a 10A load without problems. In the lower left corner you can see the antenna of the wifi module, and slightly to the right the ESP8266 module itself.

In fact, this module is an ideal template for homemade automation solutions (there are custom firmwares on github), but it is also important to note that it can work right out of the box, without any programming knowledge. And most importantly, it is several times cheaper than any GSM relay and there is no need to maintain a separate SIM card for these purposes. After all, you still have a router with the Internet in your country house. Also for cloud service The “gray” IP address, which is present in all mobile operators, is not an obstacle.

4. To use the cloud service, you need a smartphone with iOS or Android (owners Windows Phone should be despondent at this proposal). For setup and operation, the eWeLink application is used, which allows you to perform a basic connection of the device to your home local network. The process is incredibly simple: activate the programming mode by long pressing the button on the relay, connect to the wifi network that appears, open the application and set the name and password for your home network wifi All. After this, the device automatically connects to your wifi router and goes to the Internet. The settings allow you to set the state of the relay after connecting the power, as well as set a timer to turn on/off.

Among the disadvantages of the device, it is worth noting the dimensions of the case, which do not allow it to be installed in a standard socket box. This imposes a limitation on the use of the device with existing hidden electrical wiring. Also on official firmware there is no possibility of control via a local network (only through a cloud service).

But all these shortcomings pale in comparison to the price of the device. It’s unlikely that you can do it cheaper even if you pick up a soldering iron and a programmer.

The manufacturer also has a Slampsher, which is a lamp socket with an E27 socket (perhaps its board will allow it to be installed in a socket), as well as a similar module with a temperature and humidity sensor (in fact, an analogue of the Russian-made ESP Meteo). And a version with an additionally installed radio module operating at a frequency of 433 MHz, which allows you to control the load while being close to the relay. But I personally don't see any practical use for it.

I recommend buying them before they become more expensive. It is unlikely that such a freebie will continue indefinitely. For other devices from the “smart home” and “Internet of things” categories that I use, see the links below.

What do beginners who choose a wireless smart home system for the first time most often get burned by? We'll tell you how to avoid typical mistakes at the time of buying!

More and more people around the world want to turn their home into a smart one. By 2022, sales of smart home systems will more than double compared to 2018, according to ABI Research analysts. Modern wireless technologies have radically simplified the installation and configuration of smart devices, and home automation scenarios are created according to the “if...then...” principle in simple applications on a smartphone or tablet. Therefore, if previously only techno-enthusiasts could build a smart home, now even a person without advanced technical skills can cope with this task.

True, there is another side to the coin: having decided to purchase a “smart home” system, a beginner who does not have basic knowledge risks making “childish” mistakes when choosing required devices. We'll cover five of the most common ones and how to avoid them.

MISTAKE 1. Selecting incompatible components based on different smart home standards

Like many other markets high technology, the smart home has become a battleground for several incompatible standards. In the industry consumer electronics“standards wars” are ongoing: remember, for example, the recent rivalry between Blu Ray and HD-DVD optical disc formats for video players. Something similar happens with smart home systems. Today, the wireless technologies competing in the market are Z-Wave, Zigbee, Thread, Bluetooth Low Energy (BLE) and Wi-Fi. In reality, there are even more, but these five technologies are the most common today, according to analysts.

The main rule for beginners: buy smart home controllers, sensors and actuators of the same standard. Which one should you choose? Disputes on this matter have not subsided to this day: each of the technologies has its own technical features, pros and cons. Our advice is to choose a technology that guarantees at least:

● the largest selection of smart home components;

● full compatibility of devices from different manufacturers.

If both of these criteria are met, then you will be able to choose devices from the widest possible range and will know for sure that products from different brands will be able to work together. Today best technology on both these points - Z-Wave. It is used by over 700 international manufacturers, offering more than 2,400 models of interoperable smart home devices. The Z-Wave Alliance consortium is responsible for the ability of Z-Wave products to “communicate” with each other, which, based on the results of numerous checks, issues compatibility certificates to manufacturing companies.

MISTAKE 2: Selecting components of the same standard, but not RF compatible

So, you have decided on the smart home standard, purchased automation, and now you want to add additional components to it. What should you pay attention to when choosing? Important nuance— radio frequency range in which devices operate. Even within the same standard, operating frequencies may vary. It all depends on the country for which this or that component was created. For example, in Russia the frequency of 869 MHz is allocated for the Z-Wave standard, in China - 868.42 MHz, and in the USA 908.42 MHz. The Zigbee protocol operates in the 2.4 GHz frequency range in most countries. But some Zigbee devices in China use 784 MHz, in EU countries - 868 MHz, and in the USA and Australia - 915 MHz. However, most Zigbee devices in these countries also operate in the 2.4 GHz band.

Due to regional differences in frequencies, for example, a sensor purchased from a foreign online store may not be compatible with your smart home controller. Therefore, the easiest way not to make a mistake with radio frequencies is to purchase devices in trusted domestic stores that offer smart home devices operating on the “Russian” frequency. Note that the project .

MISTAKE 3. Pursuit of cheapness

The temptation to buy one of the inexpensive Asian smart home starter kits is very strong today. In Russia, for example, they are actively offered by many Chinese manufacturers of consumer electronics, including quite well-known ones. But it’s not for nothing that they say that the miser pays twice: those who love excessive savings are in for unpleasant surprises.

The first is the absence of Russian, and often even in English V mobile application to set up a smart home. Without it, adding new devices, creating automation scenarios and managing a smart home literally turns into a “Chinese puzzle” every time.

The second “surprise” is the incompatibility of invoices smart devices with European sockets without special adapters. You can expect not only additional costs for the purchase of adapters, but also low reliability of fastening smart devices in sockets, the appearance of an additional point of failure, as well as careless appearance the entire “device-adapter-socket” structure.

Third common problem— incompatibility of devices produced by different manufacturers, although the devices use the same standard/radio frequency. Chinese companies often make sure that their smart home controllers do not “see” sensors and actuators of other brands. Therefore, for example, the manufacturer’s declared support for Zigbee technology in the controller does not mean that you will be able to connect third-party Zigbee devices to your smart home.

The goal of Chinese companies is clear - to “tie” the consumer only to their products. Hence low price for smart home starter kits - sometimes almost at the cost level. The manufacturer compensates for the lost profit by the fact that each time you will have to buy additional sensors and actuators only of the same brand as the starter kit.

The list of problems with cheap Asian smart home systems goes on. Users, for example, often complain that some starter kits work fully when connected to cloud management systems hosted only on Chinese servers, which are often very slow. And when you try to select another server, some automation functions become unavailable. There are frequent complaints about the lack of qualified technical support and consulting. Therefore, before you try to save money, think about whether the game is worth the candle.

MISTAKE 4. Buying only part of the necessary smart home components

Even simple home automation scenarios involve multiple devices at once. For example, to have the lights in a room turn on automatically when you enter it, you will need motion and light sensors, as well as a dimmer/smart lamp. Remove the light sensor from this list, and the light in the room will come on even during the day when it is not needed.

Therefore, when planning a smart home system, try to decide on the main options for its use and immediately buy all the components necessary for them. Then you won’t have to waste time adding missing devices to the system and the associated reconfiguration wireless network and script editing. Our materials in the and sections will help you buy everything you need. They indicate common ways to use a smart home and lists of required components. Or write to us at , and our specialists will help you find everything you need.

MISTAKE 5. Buying extra devices

At first, to automate an apartment, a controller and several sensors/actuators included in one of the . They make it possible to create several simple automation scenarios. Mistakes with purchasing extra devices most often occur at the stage of system expansion. For example, if your home has central heating and you don’t use electric heaters, then buying a smart thermostat to control them is clearly unnecessary. But it happens that extra devices are purchased at the very first stage. For example, if you rent an apartment for a short period of time and want to automate it, then it is hardly worth buying relays and dimmers built into sockets and switches for this. For such cases, overhead devices that are easy to dismantle and take with you when moving are better suited.

conclusions

As you can easily see, “childish” mistakes when choosing components of a smart home system are easy to avoid. It is enough to have basic knowledge about wireless standards home automation, decide in advance on the scenarios for using a smart home and use the services of reliable domestic stores offering.

If you yourself want to understand the intricacies of choosing, installing and configuring smart home components, then we will help you.

Having trouble choosing devices? No problem!

Specialists of the “My Brownie” project are always happy to help: just write to us at info@site with the subject “Need help in selecting components”!

Based on our Wiren Board platform (compact industrial computer with Linux and different interfaces) we made a sophisticated controller for home automation Wiren Board Smart Home(ARM9 64MB RAM, GSM/GPRS, Ethernet, Wi-Fi, USB, 2xRS-485/Modbus, CAN, 2 relays, ASK/FSK radio module 433MHz, NRF24L01+, etc.), to which you can connect a bunch of all kinds of wired and wireless actuators and sensors from different systems and manufacturers. The device is ready and tested. We are opening orders for devices from the first large batch with delivery before the May holidays at a special price.

Motivation

Even after our very first article, many enthusiasts wrote to us that they would like to use our single-board computer as the basis of a smart home.

We worked on this issue and realized that on the basis of our Wiren Board platform it is possible to make a good controller for home automation, which will allow you to control actuators and sensors in the medium, cheap and ultra-cheap price categories (see below).

In addition to the functionality that is found in a regular Wiren Board, namely:

• ARM9 454Mhz, 64MB RAM, 4GB+ ROM running GNU/Linux 3.13
• GSM/GPRS modem
• Wi-Fi (including in access point mode)
• Ethernet (with passive PoE 12-15V)
• 2xUSB-host
• RS-485/Modbus
• ADC inputs
• battery operation

were added:

• CAN bus
• Second RS-485
• Two relays 220V 5A
• RTC - real time clock
• Sound emitter
• Audio output - 3.5 mm jack
• RS-232 full duplex, not optically isolated (optional)
• radio module NRF24
• and packet radio on 433 MHz.

There are expansion connectors inside: two UEXT and a USB-host.
The NFC and GPS modules were removed as unnecessary.

This time we selected a good standard case and designed the board for it. The choice fell on the D6MG DIN rail housing from Gainta. It is not very compact (106x90x57.5 mm), but the DIN rail mount allows you to securely place the controller in a standard cabinet with other equipment. In this case, the board is easily and reliably fixed by the case parts without mounting on racks. All connectors are located on both sides of the case.

In addition, we have provided for the possibility of using a plexiglass case on stands. This case is quite compact, looks good and is well suited if a more “desktop” application is intended.

It looks something like this:

We have not yet received the cut sheets for the new case, but a similar case that we ordered for the standard Wiren Board gives a rough idea of ​​what such a case will look like.

When designing, we were guided by solutions such as Evika (yes, this is still a very budget solution :)), Ninja Blocks and others.

What can be connected to the controller directly?

• low-voltage load: LED strips, locks, etc. To 4 open collector outputs
• 4 ADC inputs allow you to measure voltages up to 30 volts
• inputs R1-R4 (input resistance 0.5 kOhm) allow
  • measure low voltage
  • connect resistive sensors (measure resistance), for example temperature, humidity, gas sensors, etc.
  • work as GPIO (tolerant to external signals with levels up to 12V)
  • connect Wiegand card readers and keyboards
• inputs/outputs W1-W3 are GPIOs with built-in pull-up resistors to 3.3V. Can be used as GPIO and as bus controllers 1-wire(including the possibility of a strong lift).
  • connecting 1-wire temperature sensors, for example DS18B20
  • connection of meters with pulse outputs.
  • connecting buttons
• actuators and sensors operating via buses RS-485(Modbus) and CAN, For example:
  • devices of the Smart Home system via Modbus or A-BUS
  • lighting control (via DMX-512)
  • electricity meters
• 2 relays allow direct control of the power load ( 250V/5A).

Radio module at 433Mhz

The killer feature of our controller is transceiver at 433 Mhz. We use the advanced HopeRF RFM69H packet radio module with very good output power (+13/+20 dBm) and sensitivity (up to -120 dBm). The radio chip has a bunch of settings, supports various modulation modes, can encrypt traffic in hardware, allows you to programmatically change the carrier frequency, bandwidth, bitrate, etc. Work with the chip occurs in batch mode - the code in the userspace simply reads/writes bytes with data from the device.

What is all this splendor needed for? Using this radio module, you can receive and send signals to a variety of inexpensive devices with proprietary radio protocols. Examples:

• Chinese actuators, sensors and remote controls for wireless kits. There are a huge number of them, freely sold at ridiculous prices, including in Russia. A non-exhaustive list can be found; in addition, they have been repeatedly discussed on Habré recently.
• Actuators and remote controls of the Noolite system (one, two) are very convenient, inexpensive pieces of hardware for controlling light.
• Glands from www.neroelectronics.ru
• Wireless sensors for Oregon Scientific weather stations: habrahabr.ru/post/165747
• Gateways from Wireless-X10 to X10 over a 220V network, like this
• etc.

The radio module, of course, can be used for its intended purpose - to organize a communication channel and build your own wireless networks.

In the following articles we will write in more detail about working with the radio module and show how to understand various proprietary protocols and connect interesting devices to our controller.

The design of the selected case allows you to place additional boards above the main one. We plan to release several such expansion cards in the future.

Software

The controller hardware is supported by the mainline Linux kernel with a set of our patches (3.13). We use Debian GNU/Linux 7 Wheezy as the OS.
As control software, we suggest using open projects, for example, AgoControl or . Both projects are live and have a large user base. AgoControl is a classic offline system, the web server runs on the device.
In contrast, Ninja Blocks is an interesting cloud platform. Under its control, the controller downloads data and receives commands from the cloud. A dashboard with viewing and control, and creation of scenarios are available through the web service a.ninja.is.

All software for working with hardware, for example, for working with a radio module, is made independent of specific systems, so that other software can be easily used.
We will implement full controller support for the two systems mentioned, AgoControl and NinjaBlocks.

And pre-order

The development of the controller has been completed, the first samples have been assembled and tested. To produce a large batch, all we have to do is purchase the required quantities of components and send the order to the factory.

We announce the start of pre-order sales. We are talking about real pre-orders, i.e. purchasing for real money (cards, interbank) in our online store with deferred delivery.
Pre-orders will be collected until March 15th.
The production and installation of boards will be in Russia. We have already fine-tuned the process, so we will meet a fairly short deadline. We plan to ship the controllers before the May holidays.
We will inform you about the progress of production on our website.

Why such a complicated procedure? The cost of the device greatly depends on the size of the batch. If you order in small quantities, then sell at reasonable price, unfortunately, it won't work. Virtual pre-orders, without payment, as our experience has shown, give greatly inflated figures compared to real sales. We decided not to get involved with Russian crowdfunding sites, because they charge a large commission without actually attracting buyers.

Prices

The design of our controller is modular, so the price depends on the specific configuration that can be selected in the store.

Prices start from 3900rub in a minimal configuration. For example, standard configuration: everything except CAN and NRF24, upon pre-order will cost 5000 rub, and the same thing, but without GSM, - another 500 rub. cheaper.
UPD (2014-03-10): It turned out that incomplete configurations are practically not in demand. We left only the full configuration (LAN, USB, 2 RS-485 ports, Wi-Fi, GSM/GPRS modem and 433MHz radio module, NRF24L01+ radio, CAN port) for 5300 rub.

Conclusion

We welcome your comments and suggestions (for example, regarding extension modules) here in the comments or on our forum. We will be happy to answer any questions!

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Best wishes,
Wiren Board team