In the smart home ecosystem, there are dozens of sensors and actuators responsible for security, automation of household appliances, lighting and climate control. The new user is tempted to hang the apartment with sensors, like a Christmas tree with toys. The purpose of the article is to highlight the “main composition” and consider aspects of its application.
What are the sensors
Sensors are designed to convert a physical quantity into an electrical signal. As a result, we can measure this value quantitatively (temperature, humidity) or record its change (recognize movement). The sensors listed below are commercially available from most major market players:
Actuators are understood as actuators that generate signals to influence other elements of a smart home. This is a direct action either by a signal (button) or by means of an actuator (electronic valve). The executive device can also be a household appliance controlled from a smartphone, for example, a smart air conditioner. At the same time, you can control a conventional air conditioner, but with the help of a smart remote control, which will become an intermediary between the device and a smartphone. The task in this case is one, but the solutions are different. A separate class of devices are intelligent lighting devices. Smart light is described in detail in a recent article .
Let’s take a closer look at which devices are the most necessary for building a basic home automation system. There are several options for ready-made starter kits from the manufacturer.
Old-timers of the smart home, known since the time of the first console security systems. The most common are passive infrared sensors (PIR sensors). They contain a sensitive pyroelectric element that registers a change in infrared radiation when an object moves in the control zone. The radius of such a zone is 4-8 meters, which allows you to cover the room with one sensor. The standard location is the upper corner of the wall opposite the entrance to the room.
Motion sensors are so common that they are part of other devices, such as light bulbs. Such sensors are most actively used in lighting scenarios: automatic switching on and off of light, based on activity in the room. In terms of integration with the rest of the smart home system, there are no problems, since there are many devices with different interfaces. These sensors, which have a large number of application scenarios, form the basis of a smart home.
Window/door opening sensors
Door and window opening sensors consist of two parts – a reed switch and a magnet. They are installed on the door frame/window frame and sash, and when they are separated, a sensor is triggered.
The simple and durable design has long established these sensors as an integral part of security systems. Also they are widely used in smart light scenarios. A smart home is hard to imagine without these devices.
Water leakage sensors
Most of them work due to the difference in the electrical conductivity of air and water. When water hits one of the contacts located on the bottom of the device, a signal occurs. Sensors are installed in the immediate vicinity of the likely sources of leakage: under the hose of the washing machine, next to the risers, sink, heating radiator. Also, if there is a slight slope, the lowest point in terms of level will be successful for installation.
Water leakage sensor AQARA SJCGQ11LM 1 199 *
In order for the system not only to signal an incident, but also to prevent its consequences, devices are used that shut off the water supply. Usually this is a special electronic valve, but there are also original incarnations of Chinese engineering in the form of an electric drive for a ball valve handle.
From the point of view of integration into a smart home, this system is not always convenient, since it comes as an independent kit. The proprietary controller will not make friends with a common gateway, and only options will remain with work through a smart outlet or support for a voice assistant. Therefore, only sensors go to the main train, and actuators go to the reserve train.
According to the principle of operation, they are similar to standard fire detectors, which are mandatory installed in new homes. When smoke particles enter the field of the sensor’s photodetector, the radiation intensity changes and triggering occurs. In this case, the siren is activated, and if the detector is addressable, then it transmits a signal to the fire department. With such equipment, there is no point in an additional smoke detector. Otherwise, the sensor is required.
Gas leakage sensors
They react to an increase in the concentration of household gas in the air. It makes sense to use in the presence of a gas stove and (or) column. It is necessary to install such sensors near gas appliances.
Temperature and Humidity Sensors
Monitoring environmental parameters is another important function of a smart home. A good climate in the house is good for the health of the family, pets and indoor plants. Temperature and humidity measurements are increasingly available within a single device. Without these sensors, it is impossible to imagine a smart home. Atmospheric pressure is added to them, but this indicator cannot be influenced, therefore it is for reference only. And two main parameters can and should be controlled.
Temperature and humidity sensor Aqara Temperature WSDCGQ11LM 1 299 *
To do this, we use air conditioners and humidifiers. These are already more expensive devices compared to sensors, they can be considered for purchase in the long term. They are also smart and help to fully automate the process of adjusting the weather in the house. If the temperature or humidity goes beyond the specified thresholds, the corresponding device will turn on. It will work until the required indicators are reached.
By the way, do not forget about the care of climate equipment. We wrote about air conditioners here .
Dealing with actuators
As basic actuators, we suggest considering smart sockets, switches, buttons and lamps.
Some smart sockets allow you not only to control the status of lamps and household appliances, but also to keep a record of power consumption. Switches and buttons are also useful for implementing lighting scenarios and turning on / off equipment.
Another handy thing is a smart infrared remote control. They can replace all other remotes for the TV, air conditioner, etc. Imagine that now you don’t have to look for them at all!
All smart home kits have a mandatory element – a control unit, also known as a gateway or control center. This is the “brain” of the system, which is responsible for managing all smart home devices and executing automation scripts. It receives data from sensors and transfers it to the manufacturer’s server for processing. Thanks to this, you can track this data in a convenient format – in an application on a mobile device, from where you can send commands to executive devices in a couple of clicks.
Smart home control center Aqara Hub ZHWG11LM
Gateways support various wireless data transfer protocols required for data exchange with all system components: Wi-Fi, Bluetooth, ZigBee, Z-Wave, RF. If there are many devices, they are combined into groups, for which hubs are used.
Standing apart are several cloud-based smart home systems that do not require a control unit. These are Apple HomeKit, Google Home and Yandex Smart Home platforms. In this case, the command from the application flies straight to the cloud, where it is processed using a library of functions from the manufacturer of a particular device. On the example of Yandex, it schematically looks like this:
Each manufacturer has its own smart home control application. All of them are able to display a list of devices, sensor readings and send commands. An example of setting up Mi Home is here , and Rubetek is here . From the point of view of third-party vendor support, Mi Home has proven itself well.
The main function of applications is to create automation scripts to achieve given conditions. It is in them that the main “trick” of a smart home consists – the automatic execution of actions without human intervention. There is another “chip”, which will be discussed later.
Voice control is tightly integrated into the smart home. All three cloud platform developers discussed above are developing their own voice assistants: Siri, Alexa and Alice. In Russian, only Alice fully understands. Voice control takes the smart home system to a completely different level, but it also has some disadvantages.
Compared to applications from smart device manufacturers, voice assistants have more modest support for devices and their functions. The list of devices that can be friends with Mi Home is much wider. In addition, Alice does not yet accept all commands for devices available in the application. Nevertheless, the list will expand, and the convenience of voice control levels these imperfections.
In order for Alice to see your devices, just install the Yandex application on your smartphone and go to the “Devices – Smart Home” menu.
Next, you need to select the manufacturer and, on the corresponding tab, combine accounts, for example, with Mi Home. The devices will then be displayed with available voice commands.
You can manage individual devices and combine them into groups. For more comfortable communication with Alice, use a smart speaker.
Smart speaker Yandex Station Mini black
The video demonstrates several Xiaomi + Alice smart home scenarios.
If there is still no clear understanding of which scenarios will be used, then you can take all the devices in one copy. One of the advantages of the system is scalability. Most of the sensors are battery-operated and attached with 3M tape, so adding such elements is not difficult. Do not forget to read about the compatibility of the equipment and the application or voice assistant beforehand. If you are planning installation at the repair stage, then consider options with smart relays and pre-determine power outlets for smart home devices.
Adding sensors and actuators to the system from all manufacturers is simplified as much as possible and consists of several steps:
Connect the device to the power supply (if required).
Initiate adding a device in the app. Then proceed according to the instructions of the application. Usually it is enough to press the button on the device several times.
After pairing with the device, a list of available functions will appear in the application. They can be used independently or included in automation scenarios in conjunction with other smart home elements.
A smart home is a separate engineering system that deserves a thoughtful design approach. In this case, smart devices will become your reliable home assistants.