The security device on the microcontroller with the notification on the telephone line. Scheme, description

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The security device on the microcontroller with the notification on the telephone line. Encyclopedia of radio electronics and electrical engineering

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Encyclopedia of radio electronics and electrical engineering / Microcontrollers

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The device is designed to protect the premises (shop, apartment) using a motion sensor and a door opening sensor (normally closed contacts).

If several sensors are to be used, they must be connected in series.

(click to enlarge)

The algorithm works

Immediately after turning on the power, the device starts counting the time (with one LED blinking) allowing you to leave the room without raising an alarm. The local speaker sounds for 30 seconds, giving short beeps. Then the device dials to the programmed phone number and with a certain sound signal informs that it goes into armed mode. After this procedure, the control of the sensors begins.

LED indication

One LED flashes (indicator of the presence of a 220 V network), one is constantly on.

The three LEDs are lit at the same time only during an alarm.

After the alarm messages have been processed (if the sensors have returned to normal), 2 LEDs will remain flashing, indicating that a trigger has previously occurred.

This state will remain until the first re-arming (switching off and on the device).

LEDs are installed outside the protected area on the door frame from the outside.

When the door opening sensor opens, a countdown will begin, during which the guard or the owner of the premises must turn off the device using a secret switch.

If this does not happen after a minute, the siren will turn on and dialing to the programmed number (or several numbers) will start with an alarm sound.

If motion is detected inside the premises (motion sensor), the alarm will rise instantly (it is assumed that the intruder did not enter through the doors) and dialing will begin with an alarm sound.

The device also has an incoming call answering mode. The answer will be one tone if there was no alarm and another if the sensor was triggered.

This function is useful if the landlord was out of the coverage area of his mobile phone for some time and was not able to receive an alarm call.

Simply put, a family that is, for example, on vacation will always be able to find out by phone whether everything is in order at home.

The operation of the entire device is controlled by the 16F628A microcontroller. The HEX file is programmed with a random phone number. For firmware for the device, contact the author.

The security device on the microcontroller with the notification on the telephone line. Printed circuit board

The security device on the microcontroller with the notification on the telephone line. Location of elements

Firmware in HEX format and board layout in lay format

Author: Sergey, Kremenchuk, 8-050-942-35-95, blaze@vizit-net.com, blaze2006@ukr.net; Publication: cxem.net

See other articles Section Microcontrollers.

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