The burglar alarm, contrary to popular belief, did not appear with the opening of electricity, but much earlier. As soon as people began to have something to protect - prey, property, life, they thought about how to do it as efficiently as possible. And the solution was found.
Trying to protect themselves from a sudden invasion, primitive people probably did not use alarms, but real traps. Pits disguised by foliage, traps from nets and loops, stones and spears flying out of hiding places. But all these tricks required not only ingenuity, but also caution - for their creator could become a victim of such traps.
From birds to bell
But live "signaling", for example, a dog, was universal. A keen sense of smell and keen hearing made these animals good watchmen, and a resounding barking informed the whole area about the approach of a stranger. And the impressive appearance of the dog was doing its job. True, in history there were watchmen much better than dogs. There is a well-known legend about how the geese saved Rome. When the Gauls decided to climb the fortress wall at night, neither the dogs nor the sentries noticed them. Everyone was asleep. But suspicious rustles heard domestic geese and cackled, waking the Romans.
The Egyptian pyramids also had their own burglar alarms. Since the pharaohs were buried with many decorations, there were already enough hunters to profit even then. Local craftsmen made a lot of efforts so that people did not disturb the peace of the Egyptian kings. Mechanical traps were often placed inside the pyramid. For example, collapsing floors or ceilings, false exits and mazes.
In the Middle Ages, although the development of security systems slowed down, it did not stop. Moreover, in those days, scientific thought progressed more in Asia. So, in medieval Japan, to protect a rich home, they invented a "singing floor" - "uguisu bari" (translated as "nightingale floor"). When walking on it, the boards seemed to sing with the voices of birds. Of course, very few people paid attention to this during the day, but in the silence of the night, the "nightingale trills" were perfectly audible. The secret of the floor was simple: metal plates were installed on the inside of the boards. Stepping on the floorboard, a person involuntarily squeezed the plate, and it made a sound similar to a bird's trill.
In Europe, the development of signaling was developed only during the Renaissance. As a rule, these were mechanical devices. The most common is a stretched rope that, when a window or door was opened, would pull the hammer that beats on the bell. The mechanics also came up with an alarm in the form of a lever that was connected to the door. When it was opened, the second end of the lever beat a bell, which attracted the attention of the owners of the dwelling. In the 18th century, an English inventor created an alarm that caused the chimes to sound when the wrong key or other device was used to open the door. This allowed the owners of the house to know that someone was trying to get into their house.
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Breaking the circuit …
The impetus for the emergence of a new type of alarm was the discovery of electric current. Physicists quickly began to describe the effects that accompanied the movement of electrons and ions, and inventors began to implement them in practice.
In 1853, one of the first electrical alarms was patented by Priest Augustus Russell Pope of Somerville, Massachusetts. His device was powered by a power supply (battery) and was an electrical circuit in the form of a conductor attached to a window or door. When the door was opened, the contact was interrupted, the circuit was opened, respectively, and the electromagnet holding the spring stopped working. The idea was good, but not "brought to mind."
Pope's signaling was viewed as a curiosity until an enterprising man named Edwin Holmes decided to buy it in 1857. The author of the invention only threw up his hands - all rights to his brainchild belonged to the Holy See in Rome. But for $ 1,500, the businessman secured the purchase of a patent from the Pope himself. After reworking the circuit a little, Holmes began to produce electrical alarm kits in his workshop in Boston.
But businessmen who wanted to keep their stores and warehouses intact were skeptical about his innovation. In fact, a live watchman not only monitored the safety of the object, but could physically resist the robbers. And the alarm gave only a sound notification, which still needed to be heard. And the reliability of the electric battery raised questions. In general, Holmes's business did not go in Boston. But he did not despair and in 1859 he moved to New York, where several shops and stores were robbed every night. By 1866, Holmes had sold and installed 1,200 electric alarms, actively promoting his products in newspapers. A few years later, Holmes improved the system by sending a signal about penetration not to the bell, but to the police station. Now the thieves didn't even know if the alarm had gone off. Or maybe she doesn't exist at all ?!And they calmly did their dirty work, not realizing that the policemen were already rushing to them.
Commercial success prompted Holmes to send his matured son back to Boston to once again conquer the market. It is worth noting that the new signaling model was already much more effective than the previous one, but Holmes Jr. went further and began to use the existing telephone network instead of a separate line. This made it possible to extend the security alarm system to 700 objects. The father appreciated his son's innovation, and soon the burglar alarms were already using the telephone network in New York.
In 1905, the American Telephone and Telegraph Company (AT&T Company) bought their business from the Holmes. From that moment on, the alarm system began to be supplemented with new functions, such as a fire warning and an emergency call system (panic button).
Salvation for the Hermitage
It should be noted that mechanical and other alarms did not give up their positions until the 20th century. In those days, electricity was still considered an insufficiently studied thing, and therefore unreliable. In 1883, the American George Pratt patented the first perimeter "Burglar Alarms and Animal Traps". A wire or rope was located along the boundaries of the object, holding the load above the firing pin with a powder charge. When the rope broke, the load fell, the charge exploded, signaling a violation of the perimeter.
In another version from 1890, the rope pulled the trigger of a pistol with two multidirectional barrels. Moreover, the platform with the weapon could rotate 360 degrees. Thus, the intruder could be killed on the spot, and given that the trigger was pulled by him, no one was responsible.
But Pratt's signaling had no prospects, because already in the 1890s, scientists had invented a photocell. Thanks to him, the electrical circuit could be interrupted by a second delay in lighting. For signaling, they began to use light-beam signaling devices, where the stream of light falling on the photocell became a kind of "air" wire, interrupting which, the circuit was opened, and an alarm was given.
In the 1920s, a fundamentally new type of signaling was developed in the USSR. The experiments of the laboratory of Academician Ioffe at the Leningrad Polytechnic Institute laid the foundation for the contactless security alarm system. The principle of operation of the new device was similar to the operation of a musical instrument - theremin, named after its author - engineer Theremin. When a person approached the antenna contour, the capacitance of the capacitor changed, and this change was recorded by sound emitters. These days, volumetric alarm sensors work on this principle. But in 1922, a "special" alarm was installed only at two important objects - in the buildings of the Gokhran and the Hermitage.
Of course, the development of science could not but affect the security systems. In 1953, American Samuel Bagno patented an ultrasonic motion sensor, which took into account the principle of operation of a radar, the properties of ultrasonic waves and the Doppler effect. In the 1970s, an infrared sensor was created that detects an object using thermal (infrared) radiation. In the 1990s, computer algorithms for analyzing alarms were introduced. As a result, today mankind has practically unlimited possibilities to protect any object or territory.
Alexey MARTOV