Good evening, dear friends! So the next weekend has come, which means you can relax or make something from a pile of used household appliances. I'm sitting in social network Vkontakte, I'm flipping through the page, and my thoughts are completely different, they think what can be useful to make. And then suddenly his eyes fell on a cell phone. I remembered that I had an old cell phone lying around in the bins, which works, but the model is outdated and the need for it has disappeared. Without thinking for a long time, I came up with the idea of ​​making an alarm out of it via a GSM channel. So let's get started.

First you need to find an old cell phone, which is not a pity to disassemble and "spoil" a little. I personally had a Siemens S65 model at hand. The old, kind, reliable model was, in principle, and now it has remained :-) Your phone must have a speed dialing function (well, for example, when you press key 2, then your saved subscriber under this key is called up).

I took it apart without problems, since I had a set of these screwdrivers for a long time. We will need a green keyboard board.

This is how it looks from the side where the buttons are pressed. We find key 2 (personally, you can use any of the numbers) and remove the round metal plate on it.

When the metal plate is removed, you should end up like mine. These are the contacts that closed when the number 2 key was pressed.

Now we take a soldering iron and carefully solder two wires there, one wire to the central point, and the second wire to the ring. Take a thin wire, otherwise your case will not close later. Now we collect everything in place, all parts of the phone should be where they were before disassembling the phone.

Everything, the phone is assembled, but two wires are sticking out, we clean them. Now we take an additional SIM card and install it in this phone. I want to say that if the SIM card is new, it will be even better, since no one will call this number and extra messages will not come either (in particular, any advertisements from short numbers). After that, we save your personal number under key 2, as a speed dial, and in your personal phone, the number of this SIM card that you inserted into this upgraded telephone with wiring, for example, under the name "Car Security". On the same phone, you can turn off the backlight of the screen, be sure to turn off the vibration, ringer. That's it, now close the two wires and wait for your phone to receive a call from the alarm of this phone. Thus, you can listen to what is happening where this upgraded phone is installed, for example, the conversation of robbers. I have a reed switch at the end of the wires (this is a glass tube, there are contacts inside it, the contacts work when a magnet is brought to it). They are in the radio store, but instead of them, you can put a regular microswitch with open contacts. Their number is not limited, you can put as many switches as you have guarded doors, for example, in a car or in a country house.
Well, I forgot to say, if the phone is very old, then let it always be on charge, so there is more guarantee that the battery has not run out. Well, that's all I wanted to tell you today. This article will improve and become more complicated, so for starters, I started with a simple one, so that even those who have never taken a soldering iron in their hands, let alone disassembled household appliances, could assemble it. Collect, try, experiment, well, share what you got out of it :-) See you soon, Dear friends! Thank you for your attention!
P.S. Here's a short video showing how it works.

The magazine contained an article by the author Lyzhin R. “GSM security system for summer cottages”. There it was proposed to use an ordinary inexpensive cell phone as a GSM security alarm. I want to say that the "offer" is very tempting, because any even the cheapest security GSM device costs an order of magnitude more expensive than the old one cell phone. In addition, the author found how to connect to a cell phone most in a simple way requiring no intrusion into its schema. And at the same time, the cell phone itself becomes a security device. To be honest, I had no idea about such capabilities of cell phones before, because everything that I managed to read earlier on this topic required changes both to the circuit of the cell phone itself and required the need for an external electronic unit of the security system.

I needed to make a security system that only responds to a reed switch on the door position. The author of the above article suggested this case use a limit switch, the normally closed contacts of which are connected in parallel with the button of the wired headset of the cell phone. But this did not quite suit me, because the end sensor is not designed to work in tandem with the front door. It does not take into account both the play in the door frame and its open contacts exposed to atmospheric and other influences. It is not for nothing that for these purposes special reed "security detectors" are used in security devices, consisting of two halves - one with a reed switch inside is placed on the door frame, and the second with a magnet inside, on the door itself. At the same time, the design of the detector allows play in the door system up to 2-3 cm, which is very important, especially if the room is wooden (the wooden opening “walks” depending on humidity and temperature), and the natural wear of the door can lead to “movements” .

But the fact is that the reed security detector works to open. That is, the door is closed - the contacts are closed, the door is open - the contacts are open. Here, the opposite is required. Therefore, I had to make an “inverter” from a low-power relay with a 5V winding.
The figure in the text shows a diagram of my version of the GSM burglar alarm. The system consists of an old Philips E-1500 cell phone with its own wired headset and charger, an IO-102-14 security detector and a V23092-A005 electromagnetic relay with a 5V winding and switching contacts.

You only need to “mock” a wired headset and a charger cable. For a wired headset, you need to open the button case and solder two mounting wires to its contacts. The charger cable must be cut and the red and black wires pulled out.

The winding of relay K1 is connected between the red and black wires through a security detector. And in parallel with the headset button, normally closed relay contacts are connected.

Now, when the door is closed, the SG1 contacts are closed and the relay winding receives current from the Z.U charger. Relay contacts "11" and "12" open at the same time. If the door opens, the contacts SG1 open, the current to the relay winding K1 stops flowing and its contacts "11" and "12" close. Since they are connected in parallel with the cell phone headset button, the phone rings the number entered in its memory. This serves as a signal that the door has been opened.

Now about the settings of a cell phone, this is described in detail in L.1, but I will allow myself to repeat briefly.
The cell phone "Philips E-1500" is used. It is necessary to install the "SIM card" only in the "SIM2" slot, while leaving the "SIM1" slot empty. On this "sim card" you need to save the only number that the cell phone will ring when the door is opened, save it under the name "1".
Next, you need to enter the "settings" menu, then "profiles", and select "silent". Then enter the "calls" menu and select the "advanced" item, then enter the "answer mode" menu and select the "automatic" item.

Now you need to block incoming SMS. This cannot be done from the phone, so you need to contact the operator on this issue. mobile communications so that the "incoming SMS" service is disabled. Or do it yourself in " personal account» on the website of the telecom operator whose SIM card you are using.

The only setting on the receiving cell phone (to which the security device will call) will be to enter the number of the cell phone installed in the protected place into the “contacts” and give it an appropriate name (for example, “Barn Guard”). As soon as the door to this barn is opened, your cell phone will ring and the display will read "Barn Security". There is no need to answer the phone, and so everything is clear.

If there are several places to be guarded, you can purchase the appropriate number of old cell phones and make several of these security devices. Accordingly, in the “contacts” of your phone there will be “Barn Security”, “Garage Security”, “Storage Security”, etc.
The choice of a suitable cell phone to work as a security device is described in detail in the article already mentioned above (L.1), but I will allow myself to repeat briefly.

First of all, the phone must have a wired headset, and it must start dialing the number stored in the memory from one press of the headset button.

There should be an auto-answer mode (or “hands free”, “car”, etc.).

Many inexpensive cell phones meet these requirements. But there are those who do not respond to the headset button, or do not react in the same way, and you need to press some buttons to dial the number. Such cell phones are not suitable to work as a security device. All this must be carefully checked "live" when buying a cell phone, because the instructions do not always reflect all the possibilities in sufficient detail.

Tarantsev N.I.
Literature:
1. Lyzhin R. "GSM - a security system for giving", f. Radio constructor, No. 3, 2016, pp. 20-23.

To protect your property, which is located in an apartment, country house or garage, different types signaling systems. GSM security systems are distinguished by high efficiency. These systems allow for continuous monitoring of the object and, in the event of an unauthorized person entering it, notifying the owner or special services about this. For this purpose, the possibilities cellular communication: You can send messages in the form of SMS or MMS, or dial out to mobile or landline numbers entered in the alarm memory module. Reliable and multifunctional security systems of this type are quite expensive - more than 10 thousand rubles for a basic configuration, which not everyone can afford. The way out in such a situation can be a do-it-yourself GSM alarm system created from a phone that is no longer used. This method is quite simple to implement, and financially carries a minimal burden.

The principle of operation of GSM-security and its main elements

In order to make an alarm with your own hands, you need to figure out on what principle it functions, and what components are included in its composition.

Main functional node such systems is a GSM-module, which provides the transmission of warning signals from the object to the owner of the house or garage. The transmission is carried out using high-frequency mobile communication waves of one of the operators whose services are used.

The alarm signal is given in accordance with the data that the electronic signaling unit receives from sensitive sensors and sensors installed at the facility. These can be devices that react to the opening of a door, a window, glass breaking, movement in a protected perimeter. Video cameras and microphones can also be used for appropriate recordings and many other functional sensors that respond to temperature increases, smoke, water and gas leaks. Sensing elements are connected to the electronic unit wirelessly using a radio channel or through wired lines.

What is required to create an alarm yourself?

The simplest option for home-made security systems is a GSM alarm system from a phone. In this case, the role of the main element - the transmitting node, will be performed by a mobile phone, which, according to its functional purpose, is designed to call the subscriber or send messages to him. This greatly simplifies the task of creating your own alarm.

In order to start developing a security system for your home, you will need basic electrical skills, a set of suitable tools and spare parts. Below is a list of what is required:

• an unnecessary, but functioning mobile phone (the phone must support the function of a quick call to a number by pressing and holding one of its function buttons);
• reed switch with magnet,
• simple household switch;
• soldering iron with solder and flux;
• recharging unit mobile phone;
• multimeter;
• conductors and insulating tape;
• mounting tools (screwdriver, pliers, etc.).

The role of the sensor, which will be triggered when a door or window is opened, is assigned to a reed switch with a magnet or to a conventional push-button switch. This kind of sensor is connected to the mobile phone using conductors.

The functioning of the alarm made by hand

A homemade GSM alarm system from a mobile phone works according to the following principle. If the sensor installed on the object is triggered, then the contacts of one of the phone keys are closed, which is used as a shortcut button. As soon as the contact terminals are connected, the quick call function will be triggered and the owner of the apartment or house will be dialed, which will warn that there is someone else at the facility. Thanks to a quick notification using such an alarm, the owner of the house will be able to call for help in a timely manner and arrive at the facility on his own, which will prevent an attacker from stealing from an apartment or stealing a car from a garage.

In addition to making a call, you can also add elements of light and sound psychological impact in the form of a siren and flashing lights to a home-made alarm system, which will work together with the subscriber's call. It is possible to install several sensors on the protected object, which will be triggered by one shortcut key or several.

The process of assembling a GSM alarm system with your own hands from the phone

Do-it-yourself GSM alarm system from a phone is created in the process of implementing several stages. On the first of them modification of a mobile phone is made. Initially, a shortcut key is selected and configured, which should work when switching the sensor contacts. To do this, the keyboard is removed from the phone, and the conductors are soldered to the corresponding contact elements buttons.

Next, a wire line is laid from the telephone to the sensor installation site. To ensure the functioning of the mobile phone, a charging unit is connected to it, which is connected to a 220 V household network. It is important that such a GSM alarm from a smartphone remains operational for a long time even when the electricity is turned off - in this case, the power is supplied from the battery built into the phone.

The next step is to install the sensor on the door or windows. One simple option is a magnetic sensor, created using a magnet and a reed switch, which is in a closed state when contacted. When the door is opened, the magnet disengages from the reed switch, which gives a signal to trigger the phone on a call. Another option for the sensor may be a simple mechanical system that will be triggered by switching the contacts of a switch of a simple design.

The last step will be the hidden location of the sensors and the calling phone, as well as the aesthetic location of the conductors between the sensor and the mobile phone.

As follows from the above, a GSM alarm from a phone is created quite simply and does not require any special knowledge and skills. At the same time, the financial costs of such a security system will be minimal, which will save several thousand rubles.

The modern market offers users a large selection of anti-theft systems and alarms for cars. Not so long ago, GSM devices appeared on sale that allow you to track activity in the car and warn the driver about possible penetration. How does such an alarm work using a mobile phone, and is it possible to do it yourself - detailed information on this issue is given below.

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The principle of operation of a homemade mobile alarm based on a phone

The principle of operation of a homemade security device based on a cell phone is quite simple. It consists in notifying the owner of the vehicle by calling his mobile phone when entering the car. Thanks to this, the car owner can find out about the state of car protection, even if he is in another city or country.

If the sensor detects a violation of the security perimeter, a short circuit occurs on the contacts of one of the keys on the keyboard. On this button, where the contacts will close, you must set the number for a quick call in advance, so the system will call the number of the car owner. When the car door opens, the controller should work, which will send a signal to the mobile.

How to do it yourself?

Despite the fact that such a system at first glance may seem quite complicated, it is quite possible to make it yourself. We invite you to familiarize yourself with detailed instruction for manufacturing.

Tools and materials

Before starting work, it is necessary to prepare all the materials, in particular:

1. You will need a mobile phone, we will consider the manufacturing scheme using an example mobile nokia 1100. In practice, this phone is practically "unkillable", so this model is perfect for performing the main function. You can take another phone, but it is important that it is equipped with a mechanical keyboard and has a quick call function. Touchscreen gadgets are not suitable for this task.
2. You will also need a headset with a microphone, it will perform the function of monitoring the sound status in the vehicle interior.
3. To make the circuit, a soldering iron with tin and rosin is useful, you also need wires for connection.
4. Reed switch or push-button controller for opening the door.
5. To ensure the smooth operation of the signaling, you will need a rechargeable battery, its capacity should be 12 volts or more.

Stages

How to make a GSM alarm for a car:

1. First of all, you must decide which button on the prepared phone you will configure for speed dialing. Using the menu, you need to set up a quick call and assign your mobile number to this key so that the system can call it at any time.
2. After that, the cellular device will need to be disassembled, disconnected and put aside the case, dismantled the metal base with the display. By doing this, you can see the circuit on which the film is applied. In case of Nokia phone 1100 film will be white.
3. Then, carefully, using a clerical knife, you will need to make two small cuts under the button that will be used to call. On the board itself, you need to lift the film, under it you can see the membrane. This membrane will flex when the button is pressed, causing the contacts on it to close. There are two contacts - the so-called patch and ground.
4. After that, you should solder an additional wire to the ground and a patch, that is, to two contacts, with a soldering iron. To do this, you will need two wires from the cable. It would be best to take the cores, as this will reduce the likelihood of false activation and operation of your signaling.
5. When these steps are completed, you will need to seal the membrane, this will prevent a possible short circuit in the future. Please note that the membrane needs to be glued, not removed, especially if you plan to use this phone again in the future for its intended purpose.

The nuances of connecting a mobile device to an alarm

So, the basic steps have been completed, now you need to connect the device.

To connect the device, you can use one of three options, we will consider each of them in detail:

1. The first option is to connect the cellular device through a relay, in this case the contacts on it will be normally open. If you prefer this option, then in this case the relay coil must be connected directly to the output of the car alarm. At the moment the home-made device is triggered, the relay winding will transmit a voltage signal, which will lead to the closing of the contacts on the installed button.
2. The next option is to use a bipolar transistor element for connection. In this case, the contacts of the transistor device will need to be soldered to the contacts on the phone key. In particular, the negative contact must be connected to the common output, and the collector to the central contact directly on the button. At this connection the control process of closing the key will be carried out by supplying voltage to the transistor through the resistor component.
   If errors are made during such a connection, then this is also fraught with false alarms. To prevent this, the resistor should be installed immediately at the output of the base of the transistor element. With this connection, the cellular phone will make a call to the specified number only if voltage is applied to the base of the transistor.
3. The third way is to use an optocoupler to connect the system. Judging by the reviews of experts in the field of automotive electronics, this method is considered the most optimal of all. Its main advantage is the ability to make a galvanically isolated circuit. The connection process itself is practically the same as the method described above, but there is one important difference. In particular, the transistor element of the optocoupler will open when the diode is turned on, which saturates its base.

Thanks to the implementation of these methods, you will be able to establish interaction with the installed cell phone. And we are talking not only about homemade alarms, but also any branded anti-theft system. To connect, you will only need to close the relay contacts or connect the device directly to the battery (the author of the video is the Alex Derial channel).

How to make uninterruptible power supply of GSM signaling?

One of the most basic aspects of this process is to ensure uninterrupted power supply to the homemade signaling. This is necessary in order for the installation to work without interruption.

To organize an uninterrupted power supply, you can use one of several methods:

1. Can be used built into a cellular device battery, with this scheme, the battery charging procedure will be carried out thanks to a mobile charger. This method is considered one of the simplest in terms of implementation, however, in this case, the battery itself will operate in constant charging mode. This can gradually destroy the installed battery.
2. Alternatively, you can use a regular battery, however, to ensure uninterrupted power supply to the cellular gadget, you will need a battery of no more than 4 volts. And the optimal load current should be no higher than 1 ampere. The device will need to be connected directly to the power terminals of the phone with a battery. The key advantage is the ability to ensure the charge of the built-in battery is not 100%, as in the previous case, but approximately 70%. The battery will perform the function of a buffer capacity, which will be used only when the main source, that is, the phone, is activated.
   In order to implement this method, you will need to remake any car charger that is equipped with the mc34063 board. The rework procedure will consist in soldering the feedback resistor element. The mc34063 circuit is by far one of the most common and cheapest, it is installed in many charging device so it's not hard to find.
3. The next way is to refuse to use the built-in battery in the cell phone and connect the system to the alarm battery. As you understand, this method is more suitable for those cars that are equipped with anti-theft systems with their own batteries. If your car has just such a signal, then you will also need a 4 volt converter, or you can use the LM317 stabilizer. Before connecting the car alarm to a power source, you will need to check the value of the output voltage. The conversion device is best placed in the battery compartment, instead of the battery.
   In order for the power to always be uninterrupted, only high-quality components of the circuit must be used. The use of cheap stabilizers, relays and converters can cause premature failure of the GSM alarm.

The use of stand-alone burglar alarms is common. There are many modifications of the wireless system, the configuration of which depends on the conditions of use, the structural features of the area, and the requirements of the owner. The price range is different, the price-quality ratio is acceptable. At the same time, a home-made GSM alarm based on improvised devices is also of interest, especially among those who are familiar with the basics of radio electronics.

GSM alarm: buy or do it yourself?

The answer to the question depends on the requirements, the request for the security installation. The variety of functionality and capabilities of wireless systems is wide. Additional equipment provided design feature this equipment. If desired, needs, it is possible to organize an autonomous scheme that is optimally suited to this object. First of all, this concerns the protection of private houses, country cottages, city apartments, car garages, etc.

But there are cases when extensive functionality is not needed, it only complicates the use of the device. Here it is recommended to purchase systems simpler, with the necessary set of features. It is not recommended to use the cheapest ones due to poor efficiency and low reliability.

If you have the desire, as well as knowledge from the field of radio electronics, radio engineering, it is possible to organize a GSM alarm system yourself. Complete set - the most basic tools, simple devices (for example, an old mobile phone, Arduino platform, GSM module, battery, etc.).

It is better to take on an independent organization of a security alarm to a specialist who will assemble it with high quality, with knowledge of many nuances. This model is suitable for installation inside a garage, a car, a small storage facility. It is recommended to entrust the protection of serious objects (residential buildings, apartments, office premises, shops) to industrial models with remote control, a branched scheme of connected sensors of various directions.

Homemade GSM alarm system from a mobile phone

Often, an independent alarm system is built on the basis of a mobile phone. Necessary set of tools, devices:

• Push-button phone with speed dialing (mandatory).
• If you want to listen - headphones with a microphone from mobile device.
• Soldering iron, related materials.
• Wiring.
• Reed switch, magnet.
• Battery up to 12V (with external power supply of the mobile).

Sequencing:

1. Open the menu of the telephone set, select the “one-button” call settings, fix the mobile number (or group of numbers) to which DTMF signal alarms, behind the specific button(s).
2. Dismantle the phone to the board with a glued film.
3. With a sharp knife, make cuts under the number that was previously determined in the menu settings for an emergency call. Raise the film, under it there is a metal membrane, which will subsequently close the contacts (grounding, "patch").
4. Solder the wires to ground, "patch". To avoid false positive, it is recommended to use the wires of one loop.
5. Seal the membrane to prevent shorting.
6. Install the reed switch on the device, the magnet on the door. To prevent a quick opening of the circuit when the door is closed, it is necessary to provide a mechanism that shifts the magnet to the side.

Options for connecting the resulting device to the alarm:

• By means of a relay (normally open contacts).
• Using a biopolar transistor.
• Optocoupler. The most optimal option, creating a galvanic decoupled circuit.

This video describes the scheme in more detail.

How to do? Variant on the Arduino platform

This scheme includes:

• Arduino platform
• GSM modem (SIM900A, SIM800L)
• Power supply, battery.

The system works simply. A connected touch sensor (motion, infrared, etc.) upon detection of intrusion indicators, sends a signal to the system, putting it into standby mode. Alarm notification (predefined sms message) is sent to the set mobile number.

A detailed connection diagram is contained in the video

System Power Methods

• From a mobile phone battery. A simple option in which the lithium battery will always be 100% charged. Over time, this will lead to its failure.
• External power supply (battery up to 12 V). It is connected to the power terminals of the phone together with its battery. In this case, the charge will be kept at the level of 70%. When the main source of electricity is turned off, the cellular battery will power the security device.
• Without mobile battery (when the device is connected to the alarm with its own power supply).

Advantages. Flaws

pros homemade security system:

• The minimum cost of initial components in comparison with industrial options.
• Autonomous operation (only periodic recharging of the phone).
• Prompt response.
• Possibility to connect several subscriber numbers.
• Options for connecting touch sensors.
• Wireless installation.

Minuses:

• The system is easily blocked when detected. Hidden installation required.
• Local actuation.
• Suppression, signal change.

The use of a do-it-yourself GSM system is justified when it is necessary to install a security device with minimal means, and the significance of the object is not high. For a house, apartment, office, it is best to use industrial security modifications that are more reliable, efficient, and functionally diverse.

Friends! More interesting stuff:

Scope of application of GSM security alarm systems
GSM burglar alarm: short review
Security gsm alarm system for summer cottages