Do-it-yourself GSM alarm system. Scheme, description

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ENCYCLOPEDIA OF RADIO ELECTRONICS AND ELECTRICAL ENGINEERING
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Do-it-yourself GSM alarm system. Encyclopedia of radio electronics and electrical engineering

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Encyclopedia of radio electronics and electrical engineering / Security and alarm via mobile communication

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This development is dedicated to economical GSM signaling using a Siemens 35/45 series phone and an 8-bit PIC16F628A microcontroller from Microchip.

Also, the relay function is separately built into this GSM alarm system - it allows you to remotely switch any load using dial-up, gsm-c45.narod.ru/GSM_3.html.

Currently, the so-called GSM alarms have become very popular. GSM signaling in the general case is a block (GSM controller) to which sensors (sensing elements) and a GSM modem (or cell phone) are connected. It is very convenient to build a GSM alarm system based on outdated Siemens C35 (C45…) cell phones. GSM alarm is very well suited for the protection of any remote objects (garages, warehouses, cottages, kiosks, etc.). All that is necessary for the operation of this system is the presence of electrical energy, and a fairly stable cellular connection.

The principle of operation of the GSM alarm (Fig. 1) is to receive and process data from the sensors installed at the facility by the GSM controller and, in the event of an emergency situation (sensor triggering), notification through the cellular communication channel of any operator (cell phone). In addition, an external power supply is connected to the GSM controller and, if necessary, an audible siren (to the output relay).

Do-it-yourself GSM alarm system. The principle of operation of GSM alarm

Schematic diagram of the GSM controller is shown in the figure below. The GSM controller is based on the PIC16F628A microcontroller. The scheme does not contain expensive and hard-to-find details.

Do-it-yourself GSM alarm system. Schematic diagram of the GSM controller

List of electronic components used in the GSM controller

DD1 - PIC16F628A-I/P with firmware, gsm-c45.narod.ru/PIC16F628A.html
ZQ1 - 4 MHz
C1, C2 - 25pF
C3, C4, C5, C8 - 0,1mF
C6 - 360pF
C7-220/10
K1-BS115C-12A-5V
VT1 - KT815A (KT829A)
R1, R4, R5 - 4,7K
R2, R3 - 150
R6-1K
R7, R8 - 510
R9-47K
LED_R - GNL-3012HD (red) or any other red color and 3 mm in diameter.
LED_G - GNL-3014GD (green) or any other green color and 3 mm in diameter.
VD1, VD2 - 1N4007
VD3, VD4- 1N4148 (KD522)
XS1 - XS3 - 340-021-12 (blue)
XS4 - 340-031-12 (blue)

A standard interface connector is used as a connector for a Siemens phone, they can be easily found on radio markets and in stores selling electronic components.

An external power supply is connected to XS1, which should provide a voltage of 6 - 8 volts at a load current of at least 300 mA. You can use a transformer charger from a non-Chinese cell phone. The controller itself is powered by an integrated cell phone battery. Therefore, short-term power outages do not affect the operation of the GSM alarm. The higher the quality of the battery, the longer the GSM alarm is able to maintain its performance in case of loss of external power.

The GSM controller has two independent inputs for connecting external sensors. Any sensors with normally closed or normally open contacts are connected to XS2 and XS3. These can be ordinary buttons, reed sensors, glass break sensors, motion sensors, infrared barriers, gas leakage sensors, smoke detectors, water leakage sensors and many others. It should be noted that several sensors can be connected to one input at once (Fig. 3.a,b). In a serial chain (Fig. 3.a) those that are normally closed in standby mode (open in an emergency), and parallel (Fig. 3.b) those that are normally open in standby mode (close in an emergency).

Do-it-yourself GSM alarm system. Connecting sensors

The GSM controller has one output relay (XS4), to which, if necessary, a siren, signal lamp or other warning device is connected. The rated power of the relay power contacts is 2400 W (10A 240VAC). As you can see from the wiring diagram (Fig. 2), the OUTPUT RELAY WILL WORK ONLY IF THE EXTERNAL POWER IS PRESENT.

As a cell phone, you can use such models as: Siemens C35, Siemens S35, Siemens M35, Siemens C45, Siemens S45, Siemens M45, Siemens ME45, Siemens SL45. THIS GSM CONTROLLER WILL NOT WORK WITH OTHER PHONE MODELS.

The printed circuit board of the GSM controller without electronic components is shown in fig. 4.a. The printed circuit board with installed electronic components is shown in fig. 4.b.

Do-it-yourself GSM alarm system

On fig. 4.b, the numbers 1,3,4,6,5,8,10 number the outputs on the printed circuit board, which must be connected to the phone connector. The wire itself, going from the GSM controller to the telephone set, should not be longer than 30 cm.

Download printed circuit board in pcb format (P-Cad 2001): gsm-c45.narod.ru/images/4_1.pcb

Do-it-yourself GSM alarm system. Appearance of the GSM controller without a case with signed pins

This GSM alarm system compares favorably with the fact that the GSM controller does not have any buttons and switches, and the entire setting takes place in the first cell of the SIM card of the telephone set. Thus, in the first cell of the SIM card of the telephone, you need to write down a set of numbers that would configure the GSM controller in the way we need. Let's call the set of numbers recorded in the first cell STATUS. So, the word STATUS - is the main setting of the entire system, and MUST BE LOCATED IN THE FIRST CELL OF THE SIM CARD OF THE PHONE SET. The STATUS word is a 9 bit word.

The table describes the parameters that are configured with the word STATUS:

Do-it-yourself GSM alarm system. Table

Notes

Subscriber 1 is the owner of the telephone set, who has access to such functions as arming (for alarm mode), disarming (for alarm mode), turning on / off the relay (for relay mode). In the signaling mode, subscriber 1 is notified by dialing in case of an emergency (when the sensor is triggered), and also, with additional settings, can receive SMS messages about the loss / restoration of external power. Subscriber number 1 must be written in the second cell of the SIM card of the telephone set and look like
8-xxx-xx-xx-xxx.

Subscriber 2 is the owner of the telephone set, who has access to such functions as arming (for alarm mode), disarming (for alarm mode), turning on / off the relay (for relay mode). In the alarm mode, subscriber 2 is notified by dialing in case of an emergency (when the sensor is triggered), and also, with additional settings, can receive SMS messages about the loss / restoration of external power. Subscriber number 2 must be written in the third cell of the SIM card of the telephone set and look like
8-xxx-xx-xx-xxx.

Subscriber 3 is the owner of the telephone set, who has access to such functions as arming (for alarm mode), disarming (for alarm mode), turning on / off the relay (for relay mode). In the signaling mode, subscriber 3 is notified by dialing in case of an emergency situation (when the sensor is triggered), and also, with additional settings, can receive SMS messages about the loss / restoration of external power. Subscriber number 3 must be written in the fourth cell of the SIM card of the telephone set and look like
8-xxx-xx-xx-xxx.

SMS loss of external power supply - if bit 5 of the word STATUS is set to 1, then, in the event of loss of external power, an SMS message will be sent from the 1st cell of the SIM card to the number that this SMS was sent during configuration (see example 2 point 5) .

External power supply SMS - if bit 6 of the STATUS word is set to 1, then, when external power occurs, an SMS message will be sent from the 2nd cell of the SIM card to the number that this SMS was sent during configuration (see example 2 point 5) .

This GSM alarm system is one of the simplest devices of this kind located on the Internet. To assemble it, you need only minimal skills in working with a soldering iron and a little free time. At the same time, the GSM alarm system includes all the functions necessary for the comfortable protection of objects.

Homepage of the author of the scheme: gsm-c45.narod.ru, ICQ of the author 445024064. There are also firmware, usage examples, FAQ, etc.

Publication: cxem.net

See other articles Section Security and alarm via mobile communication.

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