We are talking about the use of a security alarm installation scheme in which, in the appropriate situation, a notification will be automatically sent to mobile phone. The market offers many such solutions.
As a rule, we are talking about installing a complex of various security sensors that will give a signal in case of unauthorized entry.
The sensors used can be:
- motion sensors;
- door opening sensors;
- window opening sensors;
- smoke sensors, carbon monoxide distribution;
- flood sensors;
- gas leak sensors;
- perimeter control sensors;
- other sensors.
Note that the alarm system not only deals with countering illegal entry, but can also solve other problems (early warning of fire, flooding, gas leaks or other issues).
One or two control panels can be installed, communication with a security company to call its employees.
Some GSM systems can be supplemented with functions that relate not to security functions, but to the Smart Home system. In this case, you can use your mobile phone to turn on or off certain electrical appliances in the house.
Attention-attracting systems (for example, a siren or a special spotlight) may also be additionally provided.
The system can be equipped with a remote control.
The peculiarity of this type of alarm is that in its simplest version it can be made independently. This choice seems reasonable when it comes to protecting a garage or personal car.
Principle of operation
A special compact is provided control device, which is actually a receiving and transmitting device that is connected to the system mobile communications and has its own SIM card and, accordingly, a telephone number.
To turn the alarm system on or off, an SMS message of a strictly defined type is sent to it. When certain events occur, a message is sent from the same number with information about what happened.
As a rule, from one to three mobile phones are notified, depending on the type security system.
Various security sensors are connected to the control device. Their connection itself can be carried out either using wires or wirelessly.
How to make and install a GSM alarm yourself
Of course, in this case we are talking about performing basic functions. Nevertheless, the system made in this way is, although simple, but at the same time quite reliable security system.
Required materials and tools
To get started, you need the following components.
- The main element of the assembled circuit is an old mobile phone. It must be push-button. Touch is not suitable for our purposes. It must also have the property that it must provide abbreviated dialing.
- You need to prepare a soldering iron. It would be helpful if you already have experience with this tool.
- Reed switch. What is meant here? This is the name of the switch that opens electrical circuit under influence magnetic field and closes when this influence stops.
- Magnet. It is needed to influence the reed switch.
- Wires.
- Regular switch.
How to install this system
- First of all, you need to install an abbreviated dialing number(meaning the number to which the notification should be sent).
- Next you need to prepare the keyboard. To do this we film upper layer and solder the wires to the key used for short dialing in such a way that when current passes, an imitation of pressing the corresponding key is performed.
- This is what we are talking about here. When you press the button, the contacts close and the button operates. If you solder a wire to both contacts and connect these wires somewhere outside the phone, this will lead to the same effect as pressing a button (the programmed number will be dialed and you will receive a signal from the security system).
- We install the reed switch on the door frame, and the magnet is in that place door leaf, which will be adjacent to it when closed. Let's run the wires to the reed switch. Thus, when the door is opened, the reed switch will work and the corresponding bell will ring.
- You need to install a switch on one of these wires. After all, the system must operate in the period of time when it is needed. At other times everything should be turned off.
- Don't forget that the phone will gradually discharge. Therefore, we will make sure that it is constantly recharged using its own charger, which will be constantly connected to the network.
- Do not forget that although we manufacture the system ourselves, similar to the circuit connecting the reed switch, you can supply an industrially made controller with various sensors connected to it. If desired, this can significantly increase the protective potential of such a security system.
Some additional notes
Button manipulation can be more sophisticated. So, you can operate the buttons in the same way to turn the phone on or off in order to save energy. This point may be relevant in a situation where it is impossible to ensure constant charging of the phone. For example, in a garage or when installing a security system in a car.
It is not advisable to use a SIM card that can be called.
Let's tell you more about connecting to buttons. It looks like this. The first picture shows the surface when removing the outer shell of the keyboard.
Shown is what it will look like when viewed from above. Next we see silver metal caps opposite each button. They allow current to flow when a key is pressed. Solder one wire to the ring contact, the other to the base. Then we put everything back together. The wires are connected.
Sensors here can be used not only those that operate on the basis of a reed switch. Main principle here is that as a result of a security breach, the corresponding circuit is closed. We can even talk about various kinds of simple mechanical devices suitable for this purpose.
Efficiency
Of course, the simplicity and low cost of installation determine the insufficient degree of efficiency of this type of system. But still, in some cases they can be useful and irreplaceable.
In any case, an alarm device is better than no security at all. In addition, for some applications (garage security, for example), this degree of security may be quite sufficient.
This article provides an opportunity to obtain information about the methods by which autonomous GSM alarms are assembled, installed and maintained. Each device of this type almost always operates on the basis of a special module. In fact, this is the same mobile phone, but without keys, screen and body. Instead of these devices, connectors for sensors are attached to the main board. GSM modules are provided by such leading corporations in the mobile phone manufacturing market as Siemens and Motorola.
Under development a large number of high-quality professional security systems from foreign manufacturers, the purchase of which is limited to a wide range of consumers. There are practically no descriptions of the principles of assembly of such devices.
DIY GSM module
Understanding the basic principles of operation of this type of alarm is necessary when starting to equip any facility with a GSM installation. The devices consist of appropriate outputs for sirens and detector sensors. When an alarm situation occurs, the device can be programmed to perform certain actions. Such control units are capable of processing voice messages, sending SMS notifications to owners of protected premises or corresponding alerts to security systems managed by law enforcement officers.
In addition to the above, GSM alarms are capable of activating light warning systems, sound sirens, and sending mass messages to several subscribers simultaneously. You need to decide on the components that you plan to install. The quality of operation and signaling capabilities will depend only on the developer.
Preparing for installation
As an example, we consider an assembled and configured homemade GSM ( security alarm) in an ordinary apartment in a multi-story building. The first step is to select all the necessary sensors. The ability to control hired workers, such as nannies, is often in demand. If you plan to develop a GSM alarm system for the protection of industrial or commercial facilities, in addition to a noise recognition device, you will also need a motion detector and devices sensitive to impacts and glass breakage, as well as sensors for monitoring smoke and interaction with magnets.
Sensitive elements transmit a signal to the GSM module if the entrance doors are opened, windows are damaged, or an attempt is made to enter the protected premises in any other way. Then, depending on the settings, the siren is activated, alerts are sent to programmed numbers, the lighting equipment is turned on, or several functions are performed simultaneously. If you assembled the GSM alarm yourself and installed it correctly, you must activate it every time before leaving the territory of the protected facility.
Glass break sensors
At this stage, you have to make a choice between reliability and aesthetic design. When selecting the first property appearance windows can change significantly. After installing the sensitive device, a transparent mesh will appear on the glass, which can be seen if you look closely.
If the solid surface of the glass is damaged, the sensor transmits a signal to the control unit, which will instantly begin performing all of the above possible actions. In order not to spoil the appearance of the surface with the mesh, new internal audio detectors are used for installation, which are directed to the windows. Such devices are characterized by unmistakable discrimination between the sound of breaking glass and any other objects.
Smoke sensors
Setting up a GSM alarm using smoke detection devices will always be relevant for any type of protected objects. It is advisable to install additional devices to neutralize fire. When creating an alarm system with your own hands, you can add great amount various devices. You need to understand that the number of connectors on a GSM module is limited, and the choice should always be made wisely.
Device distribution
In a residential area, sensors for detecting movement can be installed in the kitchen, rooms or hallway. The actions of any person who tries to enter the building without the knowledge of the owner of the apartment or the responsible employee of the enterprise will be immediately detected by special security devices.
A GSM alarm installed by yourself always requires choosing a location for the control unit and antenna. If integrated, the detector must be placed at a minimum possible distance from the window. If the antenna is portable, it will have to be installed in the area best regards signal sent from the main station. In this case, the control unit can be installed in the most convenient location. Installation in areas of the wall inaccessible to small children is recommended.
Using an old mobile phone
The development technology is very simple. On button 1 of the mobile phone there is a tape recorder icon. If you hold for a long time, you can call the number specified in advance. GSM alarm systems work on this principle.
Installation instructions mobile device is nothing complicated. The processor scans the state of the button. To close the contacts, some low-power optocoupler is suitable.
The output pulse is applied to the middle contact, and the signal level is checked. Galvanic discharge from external elements fits perfectly with the phone circuits. The optocoupler is soldered to the contacts with short conductors and secured to the mobile phone.
A small remote button is used to perform the function of key 1. When a pulse is received, a call is made. The subscriber can listen to everything that happens in the room by pressing the call button. Ordinary Charger Suitable for powering an integrated mobile phone.
GSM - security alarm with installed interface circuit
This method makes it possible to use a signal that is supplied to sound warning devices. The output of the comparator LM311 will open some time after the capacitor reaches 7 Volts. After the comparator starts operating, current is supplied from the resistor to the optocoupler. This is how the call is made.
Using a resistor, you can adjust the duration of the delay for activating the comparator. This is designed to prevent false calls during short-term alarm activation. The interface circuit is placed on a small board and installed together with the charger in one case.
Connecting the secret
Situations may arise when the password is scanned, the key fob with keys is stolen from the owner, or they are hacked so that the GSM alarm never goes off. Anyone can create a so-called secret with their own hands. It's easy to connect. The device contact for powering the LED is displayed on the interface circuit. If, after starting the engine, while the capacitor is gaining power, you do not press the secret button, a call is made.
Complete handsfree
This technology is only used for car alarm circuits. A complete HF system can be used instead of a charger. Such devices provide power and mount for telephones, improved communication quality due to an antenna, and two-way speakerphone communication.
For Nokia, the original CARK91 system can be used. will be improved thanks to such a device. Added auto-reply feature. When the volume is set to minimum, everything will be heard clearly. The microphone is installed in the cabin. The system itself can be placed in the fire extinguisher compartment.
Conclusion
Finally, it’s worth adding a few words about what a do-it-yourself GSM alarm system should look like. The circuit necessarily includes all of the above sensors. Detectors and sirens must be correctly connected to the software module ports.
The system must be installed at home before completion. repair work. In another situation, you should resort to the help of specialists so as not to create additional problems for yourself. There's always a lot left after construction waste, dirt and dust in the living area.
Modern security systems for cars are, of course, reliable and quite effective, but additional protection in the form of a GSM alarm will never be superfluous.
Small device is able to warn the owner in time about an attempt to break into the car or, for example, into the garage where it is stored.
Principle of operation
Even the simplest DIY GSM alarm system provides many advantages:
- firstly, thanks to a mobile phone (the main element of the system), even in the event of theft, finding a car is significantly simplified;
- secondly, when an attempt is made to break into the car (garage), a message is sent to the previously programmed phone number. All the owner needs is to respond to the danger signal in a timely and correct manner;
- thirdly, the cost of all structural elements is minimal. Most often, you can meet the amount of up to 1-1.5 thousand rubles;
- fourthly, with basic knowledge of electronics, assembling a circuit and testing the device takes no more than a few hours;
- fifthly, the security system will work even in the absence of power - on the battery built into the phone. At the same time, time battery life can reach several days.
Depending on the complexity of the circuit and the skills of the car enthusiast, a GSM alarm system may have the following functionality:
- transmit messages about various malfunctions in the car;
- automatically block the operation of the main nodes vehicle;
- control the device in an unlimited range (the main thing is that there is a mobile network);
- give various commands (for example, to start warming up the engine).
Best options
If a stand-alone GSM alarm system is what you need, then choose one of the options:
- buy a ready-made device in a store;
In the first case, you get a “black box” with a full set of functions (all that remains is to connect).
In the second, you must do everything yourself. It would seem that the option of purchasing an already assembled alarm system looks more preferable, but there is a big disadvantage - the high price.
Therefore, if you have minimal skills in the field of electronics, a thousand to one and a half rubles in your pocket and some free time, then it is better to do everything yourself. Moreover, there is nothing complicated.
Option one
Component materials you will need: a push-button telephone (you can use the cheapest one, but one that is functional and with good battery), a magnet, wires, a reed switch and a simple switch.
The assembly process itself is quite simple and consists of several simple steps:
- 1. Set up a call to the required number (for example, your mobile) on one of the buttons.
- 2. Remove the front panel of the mobile phone. This is necessary to gain access to contact group devices and wire connections.
But there may be several options:
- — the function of receiving and rejecting a call is on one key. In this case, one wire is soldered to it, and the second - to the number that you assigned to call the required subscriber;
- — if different keys are used for the call and hang up functions, then you need to solder a wire to each of the three keys and use a three-pin reed switch.
By the way, the advantage of this installation is that the phone will turn off along with the alarm, which can significantly save battery capacity.
- 3. Last step– installing a magnet on a door (garage or car), as well as setting up its operation.
The further principle is very simple: when the door is opened, the reed switch contacts open, and the car owner receives an alarm message about an intruder breaking into the car (garage).
A switch must be provided in the reed switch circuit, with the help of which the GSM alarm system will be turned on or off by the owner. In this case, you can choose the location of such a switch yourself. The main thing is that the toggle switch does not catch the eye of intruders.
The advantage of such a self-assembled system is absolute autonomy. The main thing to think about is the issue of constant recharging battery.
Perfect option, if the charger can be connected to the vehicle’s on-board network (in the case of installing protection in a garage, to a 220 V network via an adapter).
In this case, the phone will be constantly recharged over a long period of time.
The disadvantage of such a system is a slight delay in operation, because it must take some time to call a subscriber.
If suddenly the attackers quickly entered the garage (got into the car) and closed the door, then the circuit will be open and the signal may not reach.
But this problem can be easily solved - it is enough to equip the magnets with a special product that will prevent the circuit from opening again.
There are many options here to solve the problem. For example, one of the simplest is to install a magnet in such a way that when quick opening the door was moving.
In this case, after closing the door, the circuit will not open immediately and the GSM alarm will do its job completely.
Option 2
Here the circuit is a little more complicated, but the functionality is much richer than in the previous case.
Such a device is triggered when at least one input is short-circuited to the negative of the vehicle. At the same time, the alarm system itself has four security inputs: for the driver’s door, for all passenger doors, for the luggage compartment and, accordingly, the hood.
After turning on the power switch, you must quickly get out of the car (no more than 25 seconds). If suddenly the driver does not have time, the control LED will not light up until all the doors, hood and luggage compartment are closed. As soon as the conditions are met, the alarm will go into security mode.
When an attempt is made to steal and one of the doors is opened, the headlights turn on, and, if desired, the turn signals.
To turn off the alarm and remove all locks, just turn off the toggle switch hidden in a special place.
In the case where the attacker immediately closed the doors after the alarm went off, the blocking is not removed. At the same time, the car owner still receives an alarm call.
After 40 seconds, the control unit will poll all systems and, if there are no triggered sensors, will go into standard security mode. If, during the test, the opening of one of the doors is confirmed, the device goes into alarm mode.
As in the previous case, to implement such a scheme, you need to buy a mobile phone with the ability to quickly dial. In this case, the call will be made until the subscriber at the other end of the “wire” presses the reset button.
You can use an ATMEL product as a controller, although there are many analogues. Its advantage is affordable price and reliability. In addition, such a controller can easily be found on the market in your city.
Any 12 V devices can be used as a relay. The toggle switch for turning the alarm on and off is also not difficult to find. In this case, it is advisable to hide it away from prying eyes. The more reliable the place, the better.
The toggle switch is inserted into the alarm power supply circuit from the on-board network.
Installation rules
When installing such a device, several things must be taken into account: simple recommendations:
- Firstly, before starting work, study the gsm alarm diagram and strictly follow all the recommendations. If you bought a ready-made device in a store, work only according to the instructions;
- secondly, to install and connect the device, it may be necessary to remove the instrument panel and dismantle the protective panels under the steering wheel;
- thirdly, turn off the power (to do this, just remove the terminals from the battery);
- fourthly, install the control unit (mobile phone) in close proximity to the fuses (this will greatly simplify the connection);
- fifthly, install alarms and other sensors (if they are provided for in your circuit);
- sixth, carefully lay out the wires so that they do not interfere with the process of driving the car;
- seventh, connect the device to the on-board network.
Connection secrets
From the moment of installation, the GSM alarm system stands guard over your car, so every little detail matters. Moreover, there are a number of connection secrets that you need to know about during installation:
- The main task is to provide independent power to the device, which can be turned off and on using a hidden toggle switch (we have already talked about this).
- All wires must be laid in places where moisture never penetrates. This is necessary to avoid possible short circuit and system failure.
- Try to mount the main unit, sensors (if any) and wires as far as possible from heating and vibrating elements of the car. Otherwise, there is a high probability of system damage and failure.
- The device control unit must be kept away from the telephone, car antenna and radio to avoid interference.
- The places where the wires pass from the body to the doors or from the body to the hood must be additionally reinforced with special rubberized tubes to avoid creases and damage.
Installing such an alarm system is a responsible process, so there is no need to rush here. Each connector must be cleaned with special care and carefully insulated to prevent dirt and dust from getting on it.
conclusions
Thus, a GSM alarm system can become your reliable assistant in ensuring the safety of your own car.
All that remains is to decide on your priorities - make the device yourself (by choosing one of the options) or buy a ready-made system. But here a lot depends on the tasks assigned.
If your car already has an alarm system and you need an additional device, then why not do it yourself.
If the security system based on the GSM principle is the only one, then it is better to install a more functional security system or buy a ready-made device. In any case, it's up to you.
Currently, almost every resident has his own country house. As a rule, the dacha is empty most of the time, people live in cities, and come to their dachas only on weekends or during vacations. At the dacha, not only old, unnecessary things are often stored, but there are also many useful things that are useful in everyday life, as well as many valuable things and equipment in the house. But what happens at the dacha when it is empty?
While the dacha is empty, without owners, it can be of great interest to thieves. After all, nowadays it’s not so difficult to pick a lock and take a couple of expensive things out of the house. How to avoid this, because not everyone will find the time to come to the dacha and check the house every day?
While the owners of the dacha are working in the city, your home can be reliably protected by a GSM alarm system. Installing such an alarm system at your dacha is the most correct and reasonable decision. And in order not to waste time searching and a lot of money on purchasing such an alarm, you can make and install it yourself.
To create a GSM alarm you will need:
- An old unnecessary mobile phone with buttons (you probably have one of these lying around in an old chest of drawers or on the very top shelf);
- Magnet (sold in any store);
- Sealed contact - hermecon (regular or with three contacts);
- Switch and wires;
- soldering iron.
And besides this, you still need to have some minimal knowledge of electronics and a little time and patience.
So, the first and simplest thing to do is to set up a speed dial call to your current phone number. The first step is ready.
The next task is a little more complicated, but if you follow the instructions, everything will definitely work out. At this stage of the work, you need to disassemble the mobile phone and carefully expose the circuit board under the keyboard.
And then connect the device. There are two connection schemes. Before choosing a scheme, you need to decide: on a mobile phone, the call and failure buttons are one key or different ones.
Scheme one. If the call and failure buttons are one key, then one wire needs to be soldered to this key, and the second to the number button to which the quick call is assigned. This is done using a soldering iron. Hermekon is used in this case with a standard locking system.
Scheme two. If the call and failure buttons are two different keys, then you will have to solder an additional wire to the second button (one of the wires will be common). In this case, a sealant with three contacts will be used.
Having created the circuit according to the diagram, we move on to the third stage. On front door it is necessary to install a magnet and adjust the sealant so that the chain stays broken when touched.
The principle of operation of such an alarm is that when the door opens, the circuit closes and the phone rings a quick call to your phone number.
Where to install such an alarm is a personal matter for everyone. The most important thing is that it is protected from prying eyes and from moisture.
The result of the security system depends on the efficiency of the equipment used. Of course, even the most modern and expensive devices cannot give a 100% guarantee, but even a primitive system can scare off a burglar and prevent him from taking out the most valuable things.
You can buy it; such samples are quite cheap. But many craftsmen prefer to assemble it themselves. What comes out of this and how effectively do such devices work?
To find out the answer to this question, we will try to find out what a DIY GSM alarm system is.
The principle of operation of the security system
By installing an alarm, a person expects that it will be able to warn him in time about intruders entering the premises and turn on light or sound devices that can attract the attention of others to the protected object. Any system can cope with this task, but only if certain conditions are created for its operation. For example, for wired models prerequisite is the presence of a landline telephone on the premises.
Watch the video and see how the system works:
And only one GSM alarm system can work even during a power outage. Its operating principle is to use mobile communications to transmit an alarm message to the owner. Structurally, it is a device that contains a SIM card inside, and can also have a built-in microphone for listening to the object. Such a system is controlled using radio key fobs or via SMS messages.
DIY GSM alarm system
It is not always possible to buy an expensive industrial model of a security system. In this case, many people prefer to assemble the alarm themselves. Of course, there are many nuances in this issue, and the efficiency of the assembled equipment depends on how correctly it is resolved.
Fortunately, there are many GSM alarm models and schemes on the network detailed description. Moreover, the equipment assembled on their basis is practically not inferior in its efficiency to industrial designs. One of these simple systems We will look at DIY GSM alarms in this article.
We watch the video review, alarm for 10-50 rubles;
So, installing an alarm system in an apartment, garage or country house is correct solution. There is no need to buy equipment; you can assemble it yourself. To do this, you will need a little knowledge of electronics, a set of parts and a soldering iron, as well as a gsm alarm installation manual and instructions.
The components needed for such a system are:
- A push-button mobile phone that you no longer use
- Magnet
- Reed switch
- Wires and a regular switch
As you can see, the set of parts is very small and does not require significant investment. Usually all this is already in every house where the owner likes to collect various devices. So the alarm will be practically free.
Let's watch the video, a real working diagram:
Now, regarding the assembly process. It consists of several simple steps.
First you need to set up a call to the subscriber, namely the current phone number of the owner, with one button.
You will then have to remove the front panel to access the board and connect the pins. It depends on the modification of the device. If the hang up and power off functions belong to one button, then one wire must be soldered to it, and the other to the number key responsible for the call. Such a GSM alarm is presented in the diagram below. In the case of using separate buttons for each function, separate wires are soldered to each of them and a reed switch with three contacts is used.
This process can be visually depicted in the form of two, slightly different diagrams:
If you carefully study the presented materials, you can see that this approach allows you to turn off the phone at the same time as the alarm. This makes it possible to save battery life and will not require frequent recharging.
And then the simplest thing remains: after the circuit is mounted, a magnet is installed on the door and the reed switch is configured. The operation of such a GSM alarm, assembled by yourself, is not much different from industrial models. When the door is opened, the reed switch contacts close and a call is made from the phone to the programmed number.
Arming and disarming are performed using an additional switch. You can choose the location of its location and other devices yourself, the main thing is that they are not visible to strangers.
A self-assembled GSM alarm system turns out to be completely autonomous. The only condition for its operation is to periodically recharge the phone battery. You can install the charger into the electrical network of the room. In this case, the alarm will only work when the batteries are turned off.
The only drawback of such a system is the fact that it will take a couple of seconds to trigger until a connection is established with the number. If the thieves manage to enter and close the door during this time, the circuit will open and the alarm message will not come to you.
Let's look at another working diagram: 
However, this can be avoided if the magnet is equipped with an additional device that prevents it from repeatedly opening the circuit. There are many options for getting out of this situation. The simplest of them is to install the magnet in such a way that when the door is opened it moves slightly. In this case, when closing quickly, nothing will happen, since there will be no contact. The circuit turns off when the magnet returns to its original state. Installing a self-assembled GSM alarm system is available to everyone.
Efficiency of homemade systems
A special feature of such equipment is that you can buy and install all the components for it yourself. Her main function is an intrusion warning sent to the premises owner's phone. A sensor installed on the door is triggered when it is opened; if desired, it can be located under a rug or flooring to respond to the weight of someone entering the room.
A self-made GSM alarm system has many advantages, including:
- Minimum costs, you won’t find cheaper equipment
- Almost complete autonomy when periodically recharging the phone
- No need to pull and hide wires in the walls
However, such an alarm system also has a lot of disadvantages. And one of the most tangible is that anyone can block its work. Yes, and it only works in specific place, that is, when installed on the door, it will not react at all to penetration through the window.
Based on the characteristics of a homemade alarm, it is quite difficult to classify its operation as effective. Therefore, it is better to use industrial models, which are more functional and reliable.
The choice of a security system depends on the result expected from its use. Various alarm models on the market differ in capabilities and functions. But is it worth overpaying for complex samples, knowing in advance that they will not be useful. Unnecessary functionality only complicates the management of devices and increases their cost.
But experts do not recommend purchasing very cheap models. The most they can do is turn on the siren, but will it scare the thief? Not always and not for everyone. Alarm systems with radio sensors are also ineffective. Their signal can be easily jammed, even by using a children's walkie-talkie.
The optimal model of a security system is considered to be the one that most closely matches the characteristics of the facility and the needs of the owner. It also doesn’t hurt to think in advance about possible equipment upgrades that may be required over time.
If you choose between an industrial model and a self-assembled one, there are many nuances. For example, for a specialist in this matter, a GSM alarm system with your own hands will be assembled very quickly and in its effectiveness may not be inferior to industrial models. At the same time, its cost will be several times lower. But if you don't have necessary knowledge, then it is better to buy a ready-made model, because the safety of property depends on the quality of its work.
When deciding which model to choose, you should clarify what problems it can be used to solve. You can install a simple GSM alarm yourself. This way, you will know where the equipment is located and how it interacts, which will help you monitor its efficiency.
It won’t hurt to decide on the amount you have to purchase a finished model or assemble it yourself. After all, how reliable and effective it will be depends on the functionality of the system.
Which alarm system should you choose – expensive, cheap or make it yourself? Everyone who cares about the safety of their property should answer this question for themselves. How calmly you can leave your apartment when going on a business trip or vacation depends on how this issue is resolved correctly.