The protection of private property has always been a topical issue. Nowadays, there are many ways to protect your valuables or housing: you can hire security, set an alarm, insure, and so on and so forth. But what to do if these methods are too expensive in relation to the protected property, but it is still not desirable to leave unattended, for example, a summer house. The author will tell you how he found a way out of this situation by making an autonomous burglar alarm with his own hands!
What we will need to create an alarm:
1) Passive IR motion sensor (required for system response to intrusion)
The author bought a light switch for 300 rubles.
2) 12 volt siren (needed for intrusion alert)
In this case, a power of 105dB was used, but as you understand it depends only on your desire. The cost is about 200 rubles.
3) Battery holder
4) 6V relay,
5) insulating tubes,
6) wires.
7) the batteries themselves.
So let's analyze what we need from the signaling itself.
The alert should work for a short time and turn itself off after a certain period of time, and then work again in the standard standby mode. The system must be capable of being triggered repeatedly. Not a high voltage current, for long-term operation (at least half a year).
Let's start with the alteration of the motion sensor, it is necessary to transfer it from 220V power to 12V.
After analyzing the circuit, it becomes clear that it is able to work even with a power supply from 8 V to 30 V. Actually, with the 12V power supply we need, we must set the relay to 6V. We proceed to disassemble the sensor. The spherical part can be removed if one of the supports is bent. The fastening of the element is held on by latches.
After removing the board, it is observed that the sensor is nothing more than a passive IR receiver, the reaction of which is associated with a change in the power of the IR radiation incident on it and a simple optics system. The viewing angle of the sensor is 180 degrees.
Next, you need to power the points that are on the left. Negative and positive charges, respectively, to the charges of the power source (plus +, minus -).
The points on the right are needed to connect the relay winding. And the standard relay mounted on the sensor (it looks like a black box) must be removed.
Since there is not enough space inside the spherical shell of the sensor, it was decided to bring the relay to the base of the housing through wires.
The actual power is supplied to the sensor through the switch, and when the system is triggered, power is also supplied to the relay. Which in turn leads to the inclusion of a siren, notifying us of the penetration.
By the way, the number of possible connected sirens is not limited.
As you can see, I will lower that the siren, that the batteries are connected to the system through the terminals. Above and to the right is the switch, and the relay itself is located at the bottom left.
And so we assembled our security system!
ATTENTION! Protect your ears before checking the siren! Otherwise, you may damage your hearing, which is naturally undesirable. And don't let the siren's small size fool you, it's really very loud.
What did we get. Thanks to the regulator, it is possible to set the time on the sensor that the siren will work after identifying the penetration into the protected area. The author got from 10 seconds to 8 minutes.
The sensor is installed indoors (for example, at the door), and the siren is displayed outside.
It is important to know that after power is applied, the siren stops, so the author suggests placing the switch in a place that is invisible to the eyes.
To operate the sensor for 6 months, 16 alkaline batteries connected mixed will suffice.
The system has also been successfully tested in a freezer, which will allow us to assert its excellent performance even in winter. at -30 degrees.
After the author installed the system in the country, he revealed:
1. Glare from the water, unfortunately, can cause a false alarm of the system
2. If the sensor is swept up, then attackers can stick it with iso-tape, thereby creating blind spots.
Alexei
A dacha, detached outbuildings in the courtyard of a private house can also become an object of thieves' attacks. Installing an industrial security system in them is impractical, it will cost more than all the things stored in such premises.
But it’s not worth leaving it completely unprotected, lovers of profiting at someone else’s expense, if they don’t take away your property, they will harm the structure of the building, the restoration of which will require funds. Therefore, many believe that a simple burglar alarm will be the ideal solution; almost everyone can do it with their own hands.
What is included in such a system?
Typically, such models use an IR motion sensor, a siren and other components to assemble the device. But since wired detectors are designed to operate from a 220 V network, it will have to be upgraded and converted to 12 V. To do this, a 6 V relay is added to the circuit. Power is supplied to the sensor through a switch. When the device is triggered, the voltage is supplied to the relay winding, it works and leads to the activation of the siren.
If necessary, up to several sound signaling devices can be connected to such a circuit. The presence of a regulator in the sensor allows you to set the signaling time after the siren is triggered, usually it is no more than 10 seconds. The circuit is turned off using a special device that is switched by a key.
The considered simple burglar alarm is one of the most primitive, it is easy to assemble with your own hands and is economical in terms of power consumption. For example, for the winter you will need no more than 16 alkaline batteries. Such a scheme works in any conditions and is able to withstand even negative temperatures, so it is quite suitable for installation in unheated summer cottages.
Types of homemade schemes
Assembling and installing the system with your own hands has a number of advantages. It allows you to save money, eliminates the possibility of complicity of employees of the company involved in the installation, thieves. But most importantly, in the process of manufacturing and installation, you will carefully study the structure of the alarm system, you will be able to troubleshoot, make adjustments to it by connecting additional sensors and improve your design.
Watch the video, homemade security system:
There are several ways to equip a house with a simple burglar alarm, assembled and installed by yourself. The first and simplest, but at the same time the most expensive, is to invite employees of a special company who will develop the project, select the necessary equipment, install it and perform commissioning. This option is suitable for residential and warehouse premises, but is unsuitable for giving, as the costs will exceed the value of the property stored there.
Another way is to buy equipment, carefully study the instructions for its installation and operation, and install it yourself. In general, there is nothing impossible in this approach.
Moreover, many trading companies are engaged in programming the control panel, which will save you from the need to purchase a programmer, study the rules for working with it and try to complete this stage of work without outside help.
For the simplest signaling option, it is required to program the device loops, connect them to the general network and store the required number of access keys in the memory. They will be required to remove and arm the object. In addition, the inclusion of a light device is programmed, and with a time limit of up to 10-20 minutes and a relay output for dialing to a mobile phone.
Watching the video, addition to the main alarm using a mobile phone;
On the market, you can find a lot of GSM modules for sending a signal to the specified number when the contacts are closed on one of the inputs. These devices are universal and can be connected to any control panel.
If you are already, then next is their connection to the programmed device, which is quite easy for anyone who is able to find the "plus" and "minus" in the circuit. Again, with self-made installation, you will be able to deal with the laying of cables in detail and in the event of a breakdown, eliminate it without problems.
Watch a video about a purchased GSM system:
For those who are not satisfied with the wired system, you can choose the wireless option. In this case, installation is even simpler, since you only need to hang the sensors in the right places and insert batteries into them. The advantage of such systems is the ability to work on one power source for up to a year, and their cost, when equipped with one or two sensors, is low.
Detectors also have their advantages. They can be moved from one place to another, if necessary, without much hassle. The option discussed above can be reduced in price by buying used equipment. This option is easy to assemble with your own hands.
Another, the cheapest, but also ineffective way is to install dummies. Such a system is unlikely to be able to frighten a seasoned thief, but it can stop the boys who decide to play pranks in someone else's dacha.
A project for a homemade alarm - is it necessary or not?
Having decided to install a security system in the house, you first have to deal with the development and execution of documentation. A professionally executed project is the basis for a future system if its installation is carried out by employees of a special company. But what about those who decide to do all the work on their own?
If you install an alarm in a public place, then the project must be mandatory, otherwise the supervisory services will not accept the system. But the house does not belong to such objects, therefore, to install equipment in it, only a sensor circuit is required, which is necessary for future maintenance.
The simplest circuits - on a time relay
We will consider only two of them. The first burglar alarm for the house, which you can assemble with your own hands, is based on a time relay. It has two groups of contacts, and one works instantly, and the second after 5-10 seconds. This is necessary so that the owner of the object, when entering it, has time to turn off the system with a special button, which is installed in a hidden place.
Full shutdown is performed by a special toggle switch. With this design, a position sensor is installed on the door frame. Before entering, a button is installed that turns on the circuit in the security mode, after the owner exits. Typically, such complexes use a 12 or 24 V relay.
Watch the video, addition to GSM alarm, relay 12 V:
The disadvantage of the scheme is the sound of the siren until the alarm is turned off by the button. To eliminate it, the system is supplemented with one more relay, the contact actuation time in which does not exceed 120-180 sec. After this interval, the siren is turned off and remains in this position until the arming mode is turned on.
The second of the proposed k, assembled by hand, is based on one relay. The operating time of the siren in it is set using a relay. And it goes into standby mode after the system is de-energized. In this circuit, a thyristor is used to ensure fire and electrical safety of the equipment.
It is designed to connect a large number of sensors for various purposes. For example, for glass, you can use detectors in the form of strips of metal foil, which are triggered when they are broken. Their connection to a common network is performed sequentially.
It is possible to use another type of thyristors. For example, the PEV-10 model with a power of up to 10 W or several with a lower rating.
If the circuit is broken, the relay will work, which will turn on the siren or any powerful bell. Additionally, a light bulb can be included in the circuit, which is an auxiliary element that does not affect the operation of the system.
Is this method of protection reliable?
The protection of property in our time is becoming the most pressing issue. And the way to solve it depends on many factors, but often the decisive among them is the cost.
It makes no sense to install an alarm, the price of which exceeds the value of the protected property. For such cases, the ideal solution is to develop and install the system yourself.
But will such an alarm be effective? In some cases, of course, it will be able to scare away thieves, but for reliable protection it is better to use professional equipment and the services of specialists. The use of console security will not only provide reliable protection, but will also allow you to return the funds if a robbery is nevertheless committed.
Modern life is unthinkable without security alarms. They are very diverse - for example, fire-fighting or burglary protection, they differ depending on the installation location and, accordingly, the required functionality. A country house also needs protection and the best option for it is a GSM alarm system.
At the present time, there are many companies that provide alarm installation services, including those with GSM technology. At first, it may seem to you that such systems are extremely complex, but in reality they are not. The main thing is to understand a few important nuances, after which you can make an alarm on your own, without resorting to outside help. It will cost several times cheaper, moreover, further maintenance of the security system will depend solely on you. In other words, you yourself will carry out preventive measures and troubleshoot.
Despite the fact that GSM alarms are installed mainly in garages, they can also be successfully used to protect the house. The simplest security system described in this article can solve many problems, as well as add confidence in the safety of your property.
To make your own alarm system, you will need:
- soldering iron and ability to work with it;
- a set of wires;
- wire cutters;
- an old mobile phone (required with buttons - modern touch models will not work);
- one-button switch;
- stationery knife;
- insulating tape;
- small magnet;
- Super glue;
- copper and telephone wires;
- a pair of metal clips;
- multimeter;
- minimal knowledge in the field of radio engineering.
After reviewing the list of necessary tools / materials, we conclude: the cost of a home-made alarm is low. If you strictly follow the instructions below, the security system will last long enough.
Do-it-yourself alarm system for the house - installation work
In essence, a GSM alarm system is an advanced mobile phone. She will call your (or any other) number if someone breaks into the house in your absence.
The idea is this: you need to make sure that the phone itself rings the last number dialed from it at the moment when the front door opens. This phone should always be on charge and lie in some box near the outlet. As soon as the door opens, invisible contacts installed on the canopies will close and thereby provoke a call from a mobile phone - you will receive a call.
Note! For signaling, you can use the cheapest phone. The notorious Nokia 1100 is perfect for this.
First stage. To begin with, cut two pieces about 1.5 cm long from metal clips - these will be hinged contacts on the door. Then take the telephone wire, remove the insulation and unravel it into a pair of internal wires. Solder the ends of each of them to the paper clips. Fix the contacts themselves on the door with superglue - one on a fixed hinged hinge, the second on a movable one.
Select the position of the contacts in such a way that they close when the door is half open. Attach the other ends of the wires to the multimeter, then ring them in the closed state (with the door open) in order to check the circuit.
Second phase. Route the wires to the place where the device will be located, hiding them under the baseboard.
Third stage. Next, move on to the phone. It must be with a SIM card, replenished balance, disabled notifications (such as an alarm clock, an incoming call, etc.). Also, he must have the last number dialed, to which a call will be made in case of hacking.
Disassemble the phone, remove the back cover and remove the battery. Then remove the front panel with buttons and gasket. You are only interested in the front, not the back - on it, after removing the keyboard, you will see the contact tracks. Choose from them the one that leads to the call button (determine it by location, because visually it does not differ from other contacts). Fix one of the copper wires with electrical tape on the semicircular contact, and attach the second to the inner one.
Note! It is very important that in this case the outer contour of the semicircular shape does not close.
Also, make sure that the tape does not block the contact to the end call button.
Fourth stage. When everything is ready, install the battery (you can throw away the case - it is not needed), using the same electrical tape for fastening (it is important that it is blue). Then turn on your phone. It may seem impossible to you, because the keyboard is no longer there, but ingenuity comes to the rescue: take a metal clip, straighten it out, making some kind of tweezers, and close the contacts under the right end call button.
After the screen has greeted you and the phone has fully booted up, try to short out the copper wires installed in the previous step. If everything is done correctly, the phone will dial the last dialed number. But if this does not happen, you will have to check all the contacts under the button again and repeat the procedure.
Fifth stage. It remains only to install the phone in the place intended for it. Connect to the copper wires coming from the telephone, the contacts leading from the door canopies. Then plug in the charger and plug it into a power outlet. Everything, the GSM-alarm system has been successfully installed.
Note! For convenience, you can install a toggle switch on one of the long wires to turn the alarm on / off.
As already mentioned, usually such an alarm is installed on the front door. We advise you to attach the contacts to the inner door between the rooms (it will always need to be closed before leaving). If an intruder enters the house, then in any case he will move from one room to another and, therefore, will open the “alarming” door. After that, a subscriber known to you will call your number, and you will be informed about the hack.
Having certain knowledge in radio engineering, such a security system can be improved to make it look more presentable, as well as to make an alarm for a car based on it.
An important point to be aware of
If an intruder enters a house with such an alarm, he will be able to quickly detect it and turn it off. A homemade security system takes a certain amount of time to operate (often a few seconds), that is, to establish a connection with your mobile phone.
If the door closes quickly, the call will be dropped. Remember this.
As a conclusion
The indisputable advantage of such a home-made alarm can be considered its non-volatility. You only need to charge the phone battery in a timely manner using a standard power supply. It is advisable to completely integrate this unit into the mains so that the phone is powered by the battery only during power outages.
We also note that today it is more expedient to install a video surveillance system. It has a lot of advantages, but it is very expensive, so in most cases people get by with conventional GSM alarms.
If you are the owner of an expensive car, then most of all this article is not for you. And if you have a rather modest car and you want to protect your car at minimal cost (which is not at all proportional to the quality), then this description is for you.
The fact is that car alarm should not cost more than 5% of its market value, which for a used car is the amount for which you cannot buy a ready-made, more or less reliable, alarm system. The danger for a car without an alarm is not only in its theft, but also in the very penetration into the salon, theft of property, documents, etc., which is very common in the current conditions.
The damage may be small, or it may exceed the value of the car itself. In the traffic police, such cases are often not considered at all, since there is little evidence for them and they don’t initiate a case at all, stating that you yourself forgot your purse or documents somewhere, but you didn’t have any money at all. My friends had several similar cases, although the cars were equipped with purchased alarms.
But the fact is that scammers and thieves have long learned to bypass not expensive (although this is for someone), and rather monetary standard alarms. And it has become much easier to open (steal or rob) a car equipped with such a standard purchased alarm system. Now there are many different scanners with which an attacker reads your alarm code when you arm your car by giving a command over the radio from the key fob.
That's it, the "bad person" already has your code and he can easily both open the car and close it without attracting attention at all. Further, I think everything is clear to everyone. Therefore, having such an alarm, you significantly increase the potential theft or theft from the car, even compared to if you just locked it with a key, without the possibility of remotely opening the doors. And if we also take into account the human factor, the master who installs the alarm for you can naturally know how to turn it off, make a duplicate, etc.
Of course, most masters are decent people, but the facts show that if there is an opportunity, then someone will always use it. Data can be transferred to interested parties and "shoot" in a year or two after the installation of the alarm. It will be almost impossible to tie this into one whole, and even more so to prove it.
There are many more arguments not in favor of standard low and middle-class purchased car alarms, not to mention the costly part.
Consider the functions that a simple, inexpensive do-it-yourself car alarm should perform:
- The alarm should respond to penetration into the car, for example, using an IR motion sensor, or from standard light buttons that are triggered when a door or trunk is opened (the cheapest option, easy to implement, but nevertheless quite functional).
- An intrusion alarm should notify with a sound, a regular signal or an additional siren. This notification should last a certain time, for example two to five minutes, and then automatically turn off.
- After the alarm is triggered, the system should switch to the unauthorized entry mode - it should work repeatedly, block the engine start, etc.
- - The car alarm must consume low current, excluding the discharge of the battery (regular or additional) during the long-term parking of the car on guard.
- The mechanism of inclusion, transfer to the mode of protection and deactivation of the alarm system. In a simple case, a small delay (5-10s), after turning on the hidden toggle switch, while leaving the car and closing the door.
- Easy to manufacture and connect with low financial costs with maximum efficiency.
Such an alarm system will reliably protect even such a work as the Six-wheeled "Cossack Hammer"
Below is one of the most simple car alarm schemes that you can make yourself.
The car alarm combines an acoustic alarm that is triggered by the short circuit of the sensors (buttons for turning on the light of the doors and trunk) and when the ignition is turned on and blocks the engine from starting.
This scheme is suitable for installation on domestic cars equipped with a classic contact ignition system (VAZ, Moskvich, Volga, etc.) and any foreign ones with a similar contact ignition system. (Previously, all cars had a contact ignition system - they turned the key - the contacts closed), Installation is also possible in many new cars.
Homemade car alarm scheme quite simple and understandable to any novice radio amateur. All details are public and cost a penny. The connection to the electrical circuit of the car is also shown in the diagram. The bold line highlights the signaling unit itself, which is assembled in a small plastic case, selected from those available or can be purchased on the radio market - to your taste.
Everything outside the bold rectangle is the electrical equipment of your car, as well as other additional elements that are introduced into the car circuit (Sensors K2 and KZ, two relays P1 and P2, toggle switch 51).
Two types of contact sensors are used - regular interior lighting switches located in the car doors (they are connected in parallel, so the diagram shows one K1 sensor and one H1 lighting lamp), and specially installed sensors (door type) under the hood and trunk lid, if the trunk not equipped with a regular switch, similar to a door switch - so that when closed, their buttons are pressed and the contacts are open. When opening, the contacts must close.
As a sound signal source of the car alarm system, the regular signal of your favorite car or an installed purchased siren can be used. The signal is switched on using an additional electromagnetic relay of sufficient power (since the current passes through the signal coil), which must be installed in the engine compartment of the car - P1. The same P2 relay is used to block the ignition system. In principle, this relay can be placed in the box of the alarm itself. Its winding is connected in parallel with the winding P1 and when the alarm relay P2 is triggered, it shunts the capacitor C of the ignition system with its contacts, which makes it impossible to spark and start the engine.
The car alarm is activated using the micro-tumbler 51, which must be installed in a "secret place" inside the car (usually somewhere under the panel), known only to you and authorized persons. After turning on the power, the device will not respond to the status of all sensors for 15-20 seconds. This time is allotted for getting out of the car and closing the doors. After this time, the car alarm goes into armed mode.
To increase reliability, you can use an independent additional small battery, this is at will, desire and financial capabilities.
Even without an independent power source, such an alarm in modern conditions will be more reliable than a simple purchase with a remote control. About the cost is clear and so.
The system is economical. In standby mode, it consumes less than 0.7 mA, the trigger mode is 1.1 mA, and the current of the signal or siren is 0.2-0.5 A
Additionally, you can add an infrared motion sensor - purchased or if one was lying around on the farm.
If the sensor for 220V must be converted to 12V (8-20 Volts). A standard household motion sensor must be opened. The spherical part is removed by bending one support. The halves are fastened with latches.
Pull out the fee. The sensor is a passive IR receiver that responds to changes in the IR radiation that hits it. Typically, the motion sensor's field of view is 180 degrees.
Another simple car alarm circuit without chips
The circuit works on a similar principle, using the same sensors as in the previous case.
Short description:
SA2-SAn - intrusion sensors (door buttons, etc.). Diodes VD5-VDn are used to isolate the sensors if they are used for other purposes. If the sensors are only for signaling, diodes can be excluded.
The supply voltage supplied from any closed sensor, through R1 C1 is supplied to VD1. The R1 C1 circuit creates a short current pulse even if the sensor is left closed. Capacitor C2 prevents the alarm from triggering when the SA1 toggle switch is turned off.
The output key and multivibrator are assembled on the elements C4, R4, R5, VT2, K1. The duration of K1 being in the on position is determined by the selection of resistor R5 (you can install a variable resistor), and in the off position - R4. The overall pulse frequency is set by C4. This part of the circuit requires more careful tuning. Approximately around 2 Hz.
On elements C3, VD3, VD4, a node is assembled, which forms a delay in the alarm operation when the intrusion sensor is closed. This is necessary to delay the operation of the siren when the owner opens the car for 4-8 seconds to turn off the device (so as not to scare others :-)). The duration of the delay is set by the capacitor C3. The discharge of the capacitor when the power is turned off is provided by the resistor R3.
In this scheme, there is no node that would turn off the alarm after a while, this is the simplest option. If desired, such a node can be modified by slightly complicating the design, or you can use an autonomous time relay with periodic reset.
VD1 - any low-power thyristor, for example KU101. You just need to select C1 (increase if the alarm does not work when the sensor is closed), R2 (decrease if it does not work) and C2 (increase if it works immediately when the circuit is turned on). Diodes - any low-power. Relay K1 - RES55A, or similar (selected according to the power of the switched current of the siren-signal). If you use a more powerful relay (more than 1A), then you will need to increase the capacitances of the capacitors C3 and C4 quite a lot (this will lead to an increase in the size of the device). Therefore, if you have a fairly powerful load, it is better to connect a powerful relay to the RES55A output. Transistors - also any, with the appropriate transition structure, and VT2 must withstand the relay turn-on current. SA1 - any small switch (tumbler).
To turn on the car alarm:
1. Turn on the SA1 toggle switch with the sensor closed (with the door open). In this position, the circuit will not turn on and can be indefinitely.
2. Close the door - the circuit switches to armed mode.
To turn off the car alarm:
1. Open the door (this will close the intrusion sensor).
2. Fast, within 8-10 seconds. disarm - turn off the SA1 toggle switch.
Sometimes it becomes necessary to install a simple and not expensive burglar alarm. Without unnecessary bells and whistles that manufacturers add to it in order to expand the functionality of their system and somehow distinguish it from other competitors. Dacha, garage, household extension or even a greenhouse, in such places it is not always advisable and profitable to install a full-fledged security system.
In this article, we will consider several devices that claim to be simple and accessible to anyone who wants to protect their property from the encroachment of uninvited guests.
What should such an alarm be able to do?
- respond to an intrusion (some external influence - movement, the door was opened, hit, etc.);
- give a sound signal to frighten off the intruder;
- be able to arm and disarm;
- It is desirable to consume a little electricity.
This device aims not so much to close access to the house, but only to scare away the thief. Hearing a loud signal, he does not want to take risks and will not climb into the room, in addition to the psychological impact, she can also attract the attention of neighbors.
Security alarm based on motion sensor
The simplest burglar alarm for a home can be made by hand on the basis of a conventional household motion sensor for lighting, which is installed in entrances to save electricity. But instead of a lighting lamp, you can install a siren.
What will be needed for this?
- Motion Sensor- you can buy at any hardware store, such as OBI or Leroy Merlin. It is necessary to pay attention to the voltage of the sensor - we need it to work from a 220V network, the viewing angle - depends on the external design of the sensor (wall or ceiling) and the lens used (can be 180 degrees wide or corridor type). The average cost is from 400 to 800 rubles;
- Siren powered by 220V. For example, PKI-3 "Ivolga-220", the average price is 250 rubles. Can be bought at radio stores;
- Ordinary switch, to disable the alarm. Anyone will do, from 100 rubles. and higher.
The connection diagram is shown below:
The motion sensor must be chosen one that has at least two types of adjustments - time setting (TIME) and sensor sensitivity (SENS). With the help of the first one, it will be possible to set the time for the triggering of our alarm, i.e. siren sound time. This value is usually set for five minutes. The second adjustment changes the sensitivity of the sensor, for example, if it does not respond to you or to reduce the so-called "false alarms".
The switch will be needed in order to turn off the device when you are in its field of view and turn it on when you leave this room. It is advisable to install the switch discreetly, so that after activating the security alarm, you would not fall into its radius of action. In addition to the siren, you can also connect a regular light bulb for a double effect on the intruder. 
The main disadvantages of such an implementation will be that after switching on, some models of motion sensors require from 1 to 10 seconds to “stabilize” and switch to standby mode. If you come across such a sensor, you need to add a time relay to the general circuit that will keep the siren turned off for the time it is turned on.
There are still miniature motion sensors on sale that operate on 12V, for example, model DD-03. You can also create a simple alarm on them, but you need to connect it to a 12 volt power source or a battery. Thanks to this, the system will be non-volatile and work even if there are power outages.
Security alarm system from a ready-made kit
The simplest security device based on autonomous signaling can work without wires. In shops for radio amateurs, you can find two options - based on an infrared sensor (aka movement) or a magnetic contact sensor that responds to opening. True, the choice is not large enough and often you have to go shopping to find the goods "in stock". Therefore, the easiest way to purchase this product is to order it in one of the major online stores.
Kit based on infrared sensor.
An example is the Chinese alarm system under the loud name "Alarm mini". It consists of the IR sensor itself, an installation bracket and one or two key fobs. The kit comes with clear instructions for installation and operation. Separately, 4 AA batteries are purchased separately, but can also be operated from a 6V power adapter (sold separately). Doing the installation yourself is not difficult.
After inserting the batteries into the device, you need to install the unit itself in such a place that its lens is directed to the protected area. There is an infrared receiver window on the front panel to control the alarm from remotes. A lens that "captures movement" in the controlled area, operation lights and a siren.
We press the button on the remote control - the green LED lights up, which means that the report went to the exit (15-20 seconds) in order to have time to leave the apartment. Then the green eye goes out - the device starts working. Now, as soon as there is any movement in the room, a person will pass, a dog or a cat will run, the red LED will light up and after 15-20 seconds a very loud siren will sound. The device is working!
Kit based on magnetic contact sensor.
An opening sensor-based burglar alarm is a basic unit that has a sensor with open contacts and a magnet to close these contacts. You need to set them against each other so that there is direct contact between them. If a thief entered the house, when the door or window is opened, these elements move away from each other and an alarm siren sounds.
Such an alarm can be used mainly to scare off intruders, and its main advantage is its low price, about 100 rubles per sensor. And very easy installation, there is adhesive tape on each part, just peel off the protective layer and stick the sensor on the front door or window.
Often such kits are used to protect the perimeter of the house at the moment when you are inside, for example, sleep at night. The sound of the siren will wake you up and you will be able to take any action to protect yourself.
Burglar Alarm Simulator
In urban high-rise buildings, it is becoming popular to set the apartment on guard, in this case, expensive equipment is bought to protect against intrusion, and the signals are transmitted to the control panel of the security company. But not every owner can afford this, and it is not always justified.
Remember on cars such a device, under the windshield, usually near the steering wheel, there is a red LED that blinks or constantly glows? He warns that the car is guarded. So for an apartment or a summer residence, there are similar designs or in another way - imitators of a security alarm. They are designed to frighten away unprepared and unprofessional thieves or burglars.
To make such a simulator, you need to buy a red LED (for example, such an AL307), a mounting box for its placement, a 100 Ohm resistor, a switch and a compartment for two batteries. For the whole set, you will need to pay about 100 - 200 rubles. Depending on the characteristics of the LED, a current-limiting resistor must be connected to it in series. The radio store will help you choose the right resistor (unless, of course, you have the Soviet AL307 LED, as in our example).
When leaving the house, we turn on the constantly glowing LED, when we return, we turn it off. Strangers will think that the apartment is on an alarm.