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Simple, reliable alarm on motion sensors

The director of one small but not very small enterprise turned to me once. He wanted to install a good alarm system on the territory of his office - warehouse, simple, reliable, and not very expensive. The territory is large, almost half a hectare, it has several warehouses, garage, a sawmill, no fences, the terrain is open, near the river and forest. Here is an example, satellite photo. Try to take control of such a perimeter, about 60 to 60 meters. And next to the forest, river, road, take what you want and go where you want.


Simple, reliable alarm on motion sensors


There is a watchman, but this does not help, he just does not have time to get around everything. After some research on the ground and analysis of labor costs, I decided to make an alarm based on motion sensors. The system is inexpensive, reliable, made on only two electromagnetic relays, does not contain any electronic blocks, installation is possible for any electrician. It works from -40 to +40, round the clock, rain, snow and wind do not interfere with it.

The idea is simple and quite doable. We take several 5 ... 10 ... 20 (many) motion sensors, connect them together in a common three-wire circuit. One wire will be zero, the second phase, and the third wire will be the outputs from all sensors connected together. We connect to this wire a good siren or bell, several LED spotlights (if necessary) and red lights (with starters to blink) on the street and at the entrance to the office, where the watchman is now sleeping calmly.

In the evening, at the end of the working day, all garages and warehouses are closed, people leave, the alarm in the office turns on. In this case, it immediately works. The bell rings, spotlights burn, a red lamp flashes in the office and on the wall of the building, on the street. After 30 ... 40 seconds, the motion sensors go into standby mode and everything calms down. Now, as soon as any warm-blooded creature larger than a cat enters the control zone of any of the sensors, the alarm is triggered, the searchlights light up, a powerful bell rings, red lamps flash. Attackers in pants wet with fear and fragrant from unexpectedness run away, the watchman sends them in pursuit of a salt charge from a berdanka, mattsenstva in place, everyone is happy, everyone laughs. In the morning, the chef arrives at the office, opens it, the alarm goes off again, the watchman wakes up and goes home. The office and all warehouses with garages open. The alarm goes off, people begin to work in the field.

The psychological effect of this alarm exceeded all the wildest expectations. It’s not that you can climb somewhere, closer than five meters to any building it is simply impossible to approach. The sensor coverage areas are about 10 meters and they overlap. As soon as they did not try to deceive this system. Useless. Any movement immediately causes alarm, and throughout the district. I made a very powerful call, 85 decibels, school. There, even dogs now do not run - they are afraid.

Recently, I installed one good friend in the same system in his new store, connecting all the warehouses, corridors and the trading floor with sensors.

Want some details? Yes please!

In the electrical goods store, we purchase automatic devices, a 6-seat shield, a couple of 220-volt relays, din-rail indicator lights, several (two, five, ten .... many) motion sensors, street lights, red lamps with starters and loud calls battlefield.








Motion sensors were installed in all areas of the store with mutual overlapping coverage areas. In order for the sensors to work reliably around the clock, the built-in light sensor (photoresistor) is sealed with black tape.
The red lamp and bell are fixed on the street, at the entrance to the store. A second red lamp and another bell were placed in the corridor.





Ready control panel. He is at work. One of the free relay groups closes the alarm input at the DVR (it is also in the store) and an alarm message is sent to the director’s email and cell phone.






Everything is the same as in the first case. In the evening we turn on the alarm, everything rings and blinks. Everyone around sees the store closing. After a minute, calls and lamps turn off, the system goes into standby mode. Does not respond to cats and mice. When you open a store in the morning, everything rings and blinks. The director goes inside and turns off the unit.

Over the past three years, I have installed such alarms in many places, not a single invisible penetration.
In one case, the alarm did not help, the watchman simply tied and cleaned the warehouse. But then a lot of people woke up and saw who and when they climbed there, the attackers were quickly found.
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9 comments
Author
You see, Valery, you perfectly understand that there are professional alarms connected to the local police department, they are put in banks and savings banks, and there are ordinary ones for protecting tomatoes or boards with pipes, as in my case. The previous commentator did not disassemble or repair motion sensors from professional alarms and does not know that the sensors in them are the same, from the same China. Only a control board with a microcontroller, it really analyzes the behavior of the “target” and the level of interference and only then gives an alarm.
The most important thing in this alarm is the psychological factor. I did not write in the article, there are three more models of video cameras with motors standing, moving from side to side and blinking with a red diode. Circus! The whole village hears the warehouse open. An intelligent, educated person will not climb over tomatoes or at the boards, he will buy them. 99% of thieves are people from another social category, they do not have higher education and will not go into electricity.
Not a single sane person will make a burglar alarm on them.

I'm apparently not sober ....))))
... In the past, he worked in a fairly large farm ... There was also a greenhouse sector. At night they cut the film and stole tomatoes from the greenhouses ...I made a budgetary version of the alarm system - I installed several of these sensors around the perimeter, and I didn’t even think up anything new “for the periphery” - they just turned on the light in all greenhouses (there were fluorescent lamps there). He joked that I take care of thieves - I turn on the light so that in the dark I don’t look for tomatoes ...
But now, thieves, for some reason did not appreciate the care. Several times the light turned on, but they did not use ... And then ... They did not come anymore ... Proud, damn it ...))))
all sane people today are hanging out in masque, but here on the collective farm

Let them hang out further. I live in the Orenburg region.
I don’t need your fees. I installed several hundred of such sensors. Only not in the security system ( shok ), and for its intended purpose - at the entrance to residential premises, to various ateliers, workshops. In garages in conjunction with a street light sensor, in closets, etc. And to none of my clients
it never crossed my mind to use them in a security system.
Of course, it’s yours, but for such a hack-work they can also bump on a pumpkin.
Author
Well, what can I say ... It’s a little fun with me, but boring with an easily predicted person .... In fact, all sane people are hanging out now, but here, on the collective farm, there’s only some misunderstanding left out what candy do. There is such a proposal - I’m telling you the address where this system is located and you can easily overcome it by wrapping yourself in a “heat-tight shell” .... Then from me all my fees that I received here, two bottles of moonshine that I won here, other debaters, and a public apology for their technical illiteracy. Well, if you do not succeed, then the very charge that the watchman has in his gun will be quite enough for you to stimulate mental activity.
Author
Good afternoon, Ivan. I am glad that you understood my humor. Yes, in the case of a large territory, almost all sensors were placed under the eaves, and in the case of enclosed spaces - as high as possible, on the ceiling. It is convenient to pull the three-wire ball screw and, naturally, in the corrugated hose. All sensors are sequentially traversed in a single line. In the main panel, from where this system is powered, there is a differential automatic control therefore I am not afraid of a leak.
I will not discuss it

Indeed, have fun. These sensors are for domestic use only. Not a single sane person will make a burglar alarm on them.
The principle of operation of the sensors is based on the capture of infrared rays from any heated body, which falls into their field of observation. Not only does it pick up, but this body must also move at a minimum speed. Inside the sensor there is a pyrometric sensor. But the protective cap is somewhat reminiscent of a facet with many lenses. When moving an object, it is these lenses that create the effect of movement. The signal arriving at the sensor is interrupted, as it were, which creates a motion signal. If the body moves slowly enough, the sensor will not work. If the body is wrapped in a heat-tight shell, the sensor will not work. If in the room where the sensor is located, heating radiators or any heat sources are installed, just to create a small draft, then the sensor's operation will shock even the most patient person.
To protect the perimeter, there is other equipment. Although, for example, a video camera with a motion detector, where a change in the position of a predetermined percentage of pixels in the frame will be perceived as an alarm.
I will not discuss this - because people who have such systems work will not thank me. The main thing is that the attackers should not know about this, but you should not tell them here.

Have fun.)) That's right - no need to talk about sensors mass-produced by the industry for many years in millions of series. )))
According to the product itself. I liked the simplicity - this is a big plus. The disadvantage is that it is necessary to drag 230 volts for all sensors, so it should be well thought out to protect the sensors from precipitation, properly lay the cables on wooden structures, and the cables themselves are more expensive than low-current ones.
Author
Hello. I wrote about this in the article, but I can repeat it in more detail: these motion sensors are designed to turn on spotlights in the dark. And so that they work during the day, it is necessary to glue the light sensor with a black tape, or rather a photoresistor, inside the device, on its printed circuit board. The dimmer should be unscrewed to the maximum.
On what principle this sensor works, I know very well, but I will not discuss it - because people who have such systems work will not tell me thanks. The main thing is that the attackers should not know about this, but you should not tell them here.
Just a few questions.
The first is where is the light sensor located on this motion sensor?
The second - do you know on what principle the motion sensor of this model works?
The rest of the questions later.

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