Simple autonomous GSM-alarm system Rexant Watchman

  • Apr 26, 2022
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This small GSM-alarm system, combined with a motion sensor, works up to 6 months on batteries, calls and sends SMS in case of alarm and can make a very loud sound with a built-in siren.

Setting up an alarm is the easiest I've ever seen: it takes less than a minute.

Simple autonomous GSM-alarm system Rexant Watchman

Autonomous GSM-alarm system Watchman (rexant.ru/catalog/gsm-signalizatsii/avtonomnaya-gsm-signalizatsiya-storozh-rexan) now stands about 4750 rubles, but you can find cheaper (I bought two pieces for 3250 rubles in the Yekaterinburg online store.

The device is powered by three alkaline (alkaline) AA batteries. The manufacturer promises up to 6 months of battery life. If you use lithium batteries, they may last for a year. The battery compartment cover, which is also the back wall, is fixed with two self-tapping screws, so it will not be possible to quickly remove the batteries from the security alarm.

A SIM card of any operator with GSM (2G) support is inserted into the alarm system.

For arming and disarming, use the radio remote control included in the kit (additional remotes are not sold, but you can buy two alarms, install them, for example, in the garage and in the country house and register both remotes in both alarms).

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In case of an alarm, the alarm turns on the siren for 30 seconds (if it is not disabled in the settings), calls the mobile phone owner and scrolls the recorded voice message in a circle, sends SMS with the word "alarm" (if sending SMS is not disabled).

The set includes an alarm system, a remote control that already has a CR2032 battery, a good hinged wall mount, self-tapping screws for mounting it, instructions.

Under the back cover there is a battery compartment, a touch keyboard, a microphone for recording a voice message and a control button.

For minimal alarm settings after installing the SIM card and batteries, it is enough to enter just one command on the touch keyboard, turning it on with the black button:

*1 phone number* (for example, *189161234567*) - setting the main number (it is important not to forget to enter the eight before the operator code).

This is enough for the alarm to start working.

You can add two more numbers with the commands *2number* and *3number*.

By default, the siren is on, to turn it off you need to enter *7* (do not forget to turn on the keyboard with the button).

It makes sense to record your voice message (by default, it says something in Chinese), for this you need to enter the command #1# and say a 6-second message into the microphone.

You can disable the sending of SMS messages in case of an alarm with the command #9#.

The alarm call cannot be turned off, you can only resort to tricks by choosing a tariff with SMS packages and keeping its balance below the cost of the call (for example, Beeline Communication Z). In this case, the alarm will not be able to call, since there will not be enough money on the account, but SMS will be sent (checked).

After pressing the ARM button on the remote control, the alarm emits a loud squeak and flashes a red LED. You have 30 seconds to leave the protected area, after which the red LED flashes again, indicating that the armed mode is activated.

When CLR is pressed, the alarm disarms (beep sounds again and the LED flashes). You can disarm the alarm by entering the room - this is given 5 seconds (however, you can take your time and remove it before entering, because the remote control signal penetrates through the walls without any problems).

When the alarm in armed mode notices movement (by the way, it does not react to cats and small dogs up to 11 kg), at first it emits a short squeak and flashes a red LED.
After 5 seconds, the siren turns on (if it has not been disabled in the settings) and sounds for 30 seconds.
After 35-40 seconds, the first number is called. If the subscriber answered, the recorded message is played in a circle, if the call is dropped, the alarm will ring again (it will not ring again, even if the second call is reset).
Then, after 10-40 seconds, an SMS with the text "alarm" arrives (if SMS sending is not disabled).

After that, the alarm system returns to armed mode and will again yell, call and send SMS when motion is detected.

If the voltage on the batteries drops below 4.1 volts, an SMS "CHANGE BATTERY" is sent.

To save battery power, the GSM path is turned on only in case of an alarm or low battery, which is why it takes at least 30 seconds to make an alarm call and there is no way to request the status alarms. When the alarm is armed or disarmed, its number is not available.

When calling and sending SMS, the LED flashes bright green. If there are any problems with the GMS path (no network signal, SIM card inserted incorrectly, etc.), when you try to make a call or send SMS, the LED will flash red. After setting up, it makes sense to seal the LED window with black tape so that the alarm is less attracted to itself attention of potential violators (the LED light will still be visible through the motion sensor window, but not as bright).

The alarm uses the popular GSM-module "SIM800L".

One of my two instances of the signaling worked perfectly, and the second one emitted during any exchange with the mobile network quite loud sounds (I think everyone heard these sounds when the phone was close to any radio equipment and columns). It turned out that the antenna wire was intertwined with the wires from the piezo emitter, when I unfolded them and pushed them apart, the sounds stopped.

My video review of the alarm:

https://www.youtube.com/watch? v=XDiDyTl-DOU

Despite its simplicity, the autonomous GSM-alarm system Rexant Watchman performs its task and will report the penetration of low-skilled thieves. Of course, if you know in advance that such an alarm is installed or navigate very quickly, in those 30-40 seconds that are required alarm to make a call, you can have time to neutralize it, but in the vast majority of cases of breaking into a summer house or garage, it warns will have time.

Peace for everyone!

© 2022, Alexey Nadezhin

For twelve years I have been writing about technology, discounts, interesting places and events. Read my blog site ammo1.ru, in Learn, Zen, Mirtesen, Telegram.
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