GSM alarm. Scheme, description

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ENCYCLOPEDIA OF RADIO ELECTRONICS AND ELECTRICAL ENGINEERING
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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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GSM alarm is designed for simultaneous control of three security inputs-sensors and notification by a call to the "owner" when any of them is triggered:

1 input - the sensor works for a short circuit to the body.
2nd input - the sensor works for a short circuit at +12 V
3rd input - the sensor works to break the loop

For the operation of the GSM security alarm, any mobile phone with the function of quick dialing of numbers preprogrammed into the memory is required.
To call each number, its own hot dial keys are used. In 90% of the phones that come across already have this function by default, you only need to "activate" it, i.e. write down the required number for dialing in the cell. The burglar alarm is connected directly to the buttons of the mobile phone, as well as to the "Data" signal on the system connector, which is used to analyze the working state of the phone.

To ensure a constant and operational state of the phone in the event of a possible loss of voltage from the phone during operation, or it is turned off for some unknown reason, the “Data” signal is constantly monitored. If the signal is “0”, the phone is turned on by successively pressing the buttons:

- the first button "Power1" is pressed, held down for 5 seconds, pause for 5 seconds, then pressing the second button "Power2" with a hold for 5 seconds.

(click to enlarge)

The security mode is activated using a toggle switch. Closed - security mode. Open - no security. Exit delay (sensors are not polled) - 60 sec. after arming.

When any sensor is triggered - a delay of 30 seconds. before starting the process of calling 3 numbers. If you do not turn the toggle switch to the off position within 30 seconds, the dialing mode for three numbers is activated. To dial the first number, the "Call_1" key is pressed and held for 1 second, then pause for 1 second and then for 1 second. the "Call_4" key is pressed.
- Pause 1 min.
For the second number, another key is used - "Call_2" is pressed and held for 1 second, then a pause of 1 second and then for 1 second. "Call_4" is pressed
- Pause 1 min.
For the third - "Call_3" is pressed and held for 1 sec, then pause for 1 sec and then for 1 sec. "Call_4" is pressed.
- Pause 1 min.

This cycle is repeated 3 times. The timing parameters and sequence of clicks can be changed in the microcontroller control program.

(click to enlarge)

For controller firmware, please contact the author. Do not forget to indicate in the letter the subject corresponding to this design. For a guaranteed response - please indicate the valid and serviceable E-mail mailboxes. Do not forget to include the name of the structure and a link to it in the subject of the letter.

The author accepts orders for the manufacture of devices for individual orders, and also sends programmed controllers complete with a printed circuit board to repeat published designs.

Author: Yakimenko Sergey, UT2HI; Publication: ut2hi.qrz.ru

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