Security system Lock GSM. Encyclopedia of radio electronics and electrical engineering

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

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The LOCK GSM security system (hereinafter - OS) is designed to protect various stationary objects from unauthorized access. The OS has two protection zones, which can be used both for security functions and for fire alarms. Both zones operate independently of each other. As sensors for security and fire alarms, sensors should be used that, in the armed mode, have a resistance close to zero and an infinitely large resistance when triggered, for example, infrared motion sensors. A 1 kΩ resistor is connected in series with the sensor. The voltage to power the sensors is taken directly from the OS. It is possible to connect two sensors of the same zone in a serial circuit, while the resistance of the resistors of each sensor must be 510 Ohm.

The OS allows you to work both in standalone mode and with notification via a GSM channel. When operating in offline mode, when an object is violated, a power load relay (PCH) is triggered, which can be controlled by a sound emitter (siren), when alerting via a GSM channel, an additional SMS is sent to a programmed telephone number indicating the event that occurred at the protected object. This requires a cellular terminal, such as a Siemens M35i with an activated SIM card, or a cell phone.

Arming and disarming is carried out using personal electronic keys Dallas Semiconductor DS1990А.

16 keys can be written to the non-volatile memory of the microcontroller. OC allows you to write keys to the microcontroller memory directly on the reader.

Main technical characteristics: (when working with Siemens M35i)

1. Number of protection zones .......... 2
2. Number of electronic keys:..........up to 16
3. Main power supply voltage:..........~220V
4. Backup voltage:..........+12V
5. Normal loop resistance .......... 1 kOhm +/- 10%
6. Operating time of the power load relay (PCH): .......... 75 seconds
7. Maximum power RCH..........12V x 0,5A
8. Current consumption in the "Protection" mode: .......... no more than 100 mA
9. Current consumption in the "Alarm" mode: .......... no more than 160 mA
10. OS exchange rate - GSM terminal .......... 19,2 kb /

OS algorithm

All sensors at the time of arming must be in a closed state. At the same time, security loops have a resistance of 1 kOhm +/- 10%. After touching the reader with the registered key, the control LED located on the reader will light up. This means that the OS is in the protection mode of the object. If during arming one or both zones were in the open state, then the setting of the armed mode will be carried out automatically after they return to their original state. To disarm, touch the reader again with the electronic key. The LED will turn off.

If an unauthorized violation of one of the zones has occurred (a security sensor is triggered, a break or short circuit occurs in the loop), the PCN (which controls, for example, a siren) immediately turns on for 75 seconds and the control LED starts flashing. At the same time, an SMS is sent to a given number (or several numbers - depending on the order of recording on the SIM card) indicating the zone of violation. If another security zone is violated during an alarm, a corresponding SMS message will also be sent, but the RCH operation time will be counted from the moment the initially violated security zone was triggered.

If, after 75 seconds, the contacts of the sensor (sensors) do not return to their original normal state, an SMS is sent that the security zones have not been restored and the PCN starts working in a pulsed mode (closed for 1 second, open for 2 seconds), and the control LED flashes at the same frequency . In case of resetting the sensors, the OS will switch to the armed mode, an SMS will be sent about the restoration of the armed zones, and the LED will continue blinking at a frequency reduced by half compared to the alarm mode. This will additionally indicate that the OS was triggered.

In case of subsequent violation of security zones, the operation algorithm will be identical to the algorithm described above.

To disable the PCH during an alarm, and, accordingly, enable the disarming mode, it is necessary to touch the reader with an electronic key.

When you try to arm or disarm the OS with an unregistered electronic key, a short-term (within 1 second) operation of the RCH occurs. After a three-time attempt to disarm the OS with an unregistered key, an SMS is sent about an attempt to select a key.

The OS also controls the loss and restoration of the main (mains) power supply. When these events are sent corresponding SMS - messages. All operating modes are displayed on the OS LCD display.

Read about different firmware versions of this security system at lock.3dn.ru/. There you can also download the fully working version 1.0 for free.

(click to enlarge)

Recommendations for self-assembly of the OS

The OS printed circuit board is designed using SMD components, which made it possible to create a fairly compact device. PCB drawings are attached - detail side view (Vid.lay file), mounting side view (Plata_SMD.lay file) and a photomask (Foto.lay file) for manufacturing a printed circuit board using a positive photoresist method, for example "POSITIV RESIST". The printed circuit boards are made in the Layout 40 program.

If you plan to use not a modem, but only a cell phone, the MAX232 chip and its strapping components can be omitted. However, we draw your attention to the fact that the phone will work unstably in the area of ​​negative temperatures. This is a problem with all cell phones, so it is advisable to use a modem, for example "Siemens M35iT". In addition, through this microcircuit, you can connect the computer's COM port to set up the OS (this will be discussed below).

It is also optional to use the LCD indicator. In this case, you will have to initialize the device, write and delete keys "blindly", which is very inconvenient.

Resistors R16 and R17 are installed directly in the motion sensor in series with normally closed contacts SMK1 and SMK2. They must have exactly the same ratings as R4 and R5, since together with them they form a balanced bridge for monitoring security loops. If you use only one guard channel, then the second channel must be shunted with a resistor.

For the modem to work, informational SMS must first be written to the SIM card. The algorithm for recording and sample SMS texts in the SIM card cells is given in Appendix Table 1: The given cell numbering sequence is MANDATORY!

The 9-pin COM is used to connect the OS to the GSM modem. In the case of using a cell phone, there is a corresponding connector on the board. To power the motion sensors, two connectors are used, from which the 12V voltage is removed. The purpose of the other inputs/outputs for connecting to the OS is given in table 2 of the appendix.

After assembling the device, carefully check the correct installation, the absence of a short circuit. When installing elements on the board, you need to take into account the following point - the device uses switching buttons that have "through" outputs, due to which they also act as jumpers. An example of such a button is shown in the figure. In it, pin 1 is connected to pin 2, and pin 3 to pin 4. If you use other buttons (not installed on the board), connect the corresponding points with jumpers made of insulated wire. Pay special attention to this!

OS setup and initialization

For adjustment, connect the corresponding circuits of the reader and the control LED to the outputs of the OS. Instead of motion sensors, turn on buttons with normally closed contacts in series with 1 kΩ resistors. To the output of the PCH (pins 1 and 2 of the OS), connect, observing the polarity, an LED with a 1-2 kOhm resistor connected in series. This LED will control the operation of the RCH. Instead of a GSM modem, connect the computer port to the 9-pin COM port with a modem cable. Please note that the output of the TX OS is connected to the input of the RX COM port. Through the terminal program you will be able to observe the modem control commands.

Connect the OS to the main (mains) and backup power source. A splash screen will be displayed on the indicator. Run any terminal program on your computer, such as COM Port Toolkit or rs232Pro. Perform OS initialization by pressing for at least 1 second and releasing the ENTER button. The OS will switch to the "Disarmed" mode, about which a message will be displayed on the LCD. After that, you can start recording keys.

  Key writing order:

1. First, the memory of the microcontroller is cleared. To do this, in the "Disarmed" mode, press and hold the ENTER button for at least 5 seconds. The display will prompt you to delete the keys and then confirm that the keys have been deleted. After that, the OS will automatically switch to the key recording mode, a message will be displayed that recording has begun and the LED on the reader will light up.

2. Briefly (lasting no more than 1 second) sequentially touch the reader with the keys (maximum - 16 keys).

3. Successful registration will be confirmed by a single flash of the reader's LED, a short PCH operation and a message on the display.

4. Approximately 50 seconds after the registration of the last key, the device will exit the recording mode, about which the following message will appear on the display: "Recording of keys is completed", while the PCH will briefly work and the LED will go out. Please note that a maximum of 16 keys can be registered. Registering the 17th key will delete the first key, the 18th the second, and so on. When registering, the duration of touching the reader must be no more than 1 second, otherwise there will be a double registration of the same key.

Touch the reader with the written key. The LCD will display a message that the OS is armed, and the terminal program will display the command AT+IPR=19200. This indicates that the GSM modem was initialized and the exchange rate was set to 19,2 kB/s.

Open the contacts of zone #1. In this case, the message "Alarm! Zone No. 1" will be displayed, the PCH will work, and in the terminal program you will see the SMS sending command: AT + CMSS = 1. A similar situation will be observed when the contacts of the second zone open. The OS will also go into alarm mode if the security loop is interrupted or shorted.

To turn off the alarm mode, touch the reader with the key. The OS will switch to the "Disarmed" mode.

Arm the OS again and unlock, then restore any armed zone. After 75 seconds, the PCN should turn off, the OS will switch to armed mode with a blinking control LED, and the AT + CMSS = 3 command will be visible in the terminal program. If the security zones have not been restored, then the PCN will switch to the pulse mode of operation and the AT+CMSS=4 command will pass.

Turn off the main (mains) power in OS armed mode. The terminal program will issue the command AT+CMSS=5, and when the main power is restored, the command AT+CMSS=6.

Take a key not programmed for this OS, and, in armed mode, touch the reader three times with it. After the third touch, the terminal program will issue the command AT+CMSS=7.

After completing the adjustment, connect standard devices to the OS - motion sensors, a siren, a GSM modem and try out the operation of the OS in real conditions.

If one of the keys is lost, for security purposes, it is necessary to delete the information about all the keys with the ENTER button, and re-register the remaining keys. In this case, when you press the ENTER button, the display prompts you to delete all keys. When the button is released, the deletion will be canceled, to confirm the deletion, you must hold the ENTER button pressed for at least five seconds. After this time, information is displayed that all keys have been deleted, the PCN is activated for a short time, the LED lights up and the OS automatically switches to the mode of recording new keys, about which a corresponding message is displayed. If you just need to add a new key, press the MENU button and write the key that will be added to the OS memory. These operating modes of the OS can also be checked at the setup stage.

If in the future it is necessary to completely turn off the main and backup power, the INITIALIZATION operation (pressing the ENTER button after power is applied) must be repeated, but the keys WILL BE SAVED in the memory, as they are recorded in non-volatile memory

Table 1

Table 2

Firmware HEX, files in LAY format you can download here (62 kb)

Author: Michael (alarm.gsm [dog] gmail.com); Publication: cxem.net

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