This article makes it possible to obtain information on how autonomous GSM signaling is collected, installed and maintained. Each device of this type almost always works on the basis of a special module. In fact, this is the same mobile phone, but without the keys, screen and housing. Instead of the indicated devices, connectors for sensors are connected to the main board. GSM modules are provided by leading corporations in the mobile phone manufacturing market such as Siemens and Motorola.
A large number of high-quality professional security systems of foreign manufacturers are being developed, the acquisition of which is limited for a wide range of consumers. Descriptions of the principles of assembly of such devices are almost never found.
DIY GSM module
Understanding the basic principles of functioning of this type of alarm is necessary at the beginning of the arrangement of any object with a GSM installation. The devices consist of a control unit with corresponding outputs for sirens and detector sensors. If an alarm 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 officials.
In addition to the above, GSM alarms are capable of activating light warning systems, sound sirens, and mass sending 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.
Preparation for installation
As an example, an assembled and configured home-made GSM (burglar alarm) in an ordinary apartment of a multi-storey building is considered. First of all, all the necessary sensors are selected. 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 device for recognizing noise, you will also need a motion detector and devices sensitive to shocks and glass breaking, as well as sensors to control smoke and interact with magnets.
Sensitive elements transmit a signal to the GSM module in case of opening the entrance doors, damage to the windows or attempted entry into the guarded room in any other way. Then, depending on the settings, the siren is activated, notifications are sent to the programmed numbers, the lighting equipment is turned on, or several functions are simultaneously performed. If the GSM alarm system with your own hands has been collected and correctly installed, you must activate it every time before leaving the territory of the protected object.
Glass break sensors
At this stage, you have to make a choice between reliability and aesthetic design. When you select the first property, the appearance of the window can change significantly. After mounting the sensitive device, a transparent grid will appear on the glass, which can be seen if you look closely.
If the entire glass surface is damaged, the sensor transmits a signal to the control unit, which will immediately begin to perform all of the above possible actions. In order not to spoil the surface appearance with a grid, new internal audio detectors are used for installation, which are sent to the windows. Such devices are characterized by an unmistakable distinction between the sound of breaking glass and any other objects.
Smoke sensors
Setting up a GSM alarm system using smoke detection devices will always be relevant for any type of guarded facility. It is advisable to install additional devices to neutralize the fire. When creating a do-it-yourself alarm, you can add a huge variety of devices to the system. You need to understand that the number of connectors on the GSM module is limited, and the choice should always be made wisely.
Device distribution
In a living room, the installation of sensors for determining movement can be carried out in the kitchen, in rooms or in the corridor. The actions of any person who tried to enter the building without the knowledge of the owner of the apartment or a responsible employee of the enterprise will be immediately calculated by special security devices.
A do-it-yourself GSM alarm system always requires a choice of location for the location of the control unit and antenna. If integrated, the detector should be placed at the minimum possible distance from the window. If the antenna is portable, it will have to be mounted in the zone of the best reception of the signal from the main station. The control unit can be installed in the most convenient place. It is recommended to install on wall sections inaccessible to small children.
Using an old cellphone
Development technology is very simple. Button 1 of the mobile phone has a tape recorder icon. With prolonged holding, you can reach the number indicated previously. According to this principle, GSM-alarm works.
Instructions for installing a mobile device is not 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, the signal level is checked. Galvanic discharge from external elements is remarkably consistent with the phone circuitry. The optocoupler is soldered to the contacts with short conductors and fixed on 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 reception key. An ordinary charger is suitable for powering an integrated mobile phone.
GSM - burglar alarm with installed interface circuit
This method makes it possible to use a signal that is fed to sound warning devices. The output of the LM311 comparator will open some time after the capacitor has set a power of 7 volts. After the start of the comparator, a current is applied in the direction from the resistor to the optocoupler. Thus the call is made.
Using a resistor, you can configure the length of the delay to activate the comparator. This is designed to prevent false calls during short-term activation of the alarm. The pairing circuit is placed on a small board and is installed together with an auto charger in one housing.
Connect a secret
Situations may arise when they scan the password, steal a keychain with keys from the owner or hack in such a way that the GSM alarm never triggers. With their own hands, everyone can create a so-called secret. Connecting it is easy. The contact of the device for powering the LED is displayed on the interface circuit. If after starting the engine during the power-up of the capacitor does not press the secret button, a call is made.
Full 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 phones, improving communication quality through the antenna, two-way speakerphone.
For Nokia, the original CARK91 system can be used. Do-it-yourself installed GSM alarm system will be improved thanks to such a device. Auto answer option is added. When setting the minimum volume, everything will be heard clearly. The microphone is installed in the cabin. The system itself can be placed in the fire extinguisher department.
Conclusion
Finally, it’s worth adding a few words about how the assembled GSM alarm system should look like with your own hands. The scheme necessarily includes all of the above sensors. Detectors and sirens must correctly connect to the ports of the software module.
It is necessary to install a house system before the completion of repair work. In another situation, you should seek the help of specialists so as not to create additional problems for yourself. After breaking the walls, there is always a lot of construction debris, dirt and dust in the living room.