Sensors for the security alarm system

02/28/2017 - 07:44

Exists many different types of sensors for the security alarm system. The majority of them will be not not considered because of complexity of manufacturing in house conditions by us, and will stop on the simplest.

So, glass of the car can protect and the ordinary tiny button (MP-1) established on a corner, fig. 3.24. It fastens to glass a corner clip under rubber sealing laying.

Krom of buttons, as sensors are most often applied the tight gerkonovy contacts which are becoming isolated at influence of a magnet. They possess high reliability and small dimensions that does possible secret placement in deepening on a framework of doors and window frames. Thus the small magnet fastens on a mobile part, for example glue (fig. 3.25).

Depending on a magnet arrangement relatively геркона, the sensor can work for short circuit or chain disconnection at operation (usually use on disconnection).

Sensitivity of contacts геркона is enough font, that it worked at distance 5... 15 mm from a magnet.

Use of only gerkonovy sensors and buttons not everywhere will be possible to provide reliable protection (a window can break).

in the Simplest way of the alarm system at a razbivaniye of a window is pasted on glass perimeter a thin and narrow strip from the metal foil, included consistently in a chain

the Fig. 3.24

the Fig. 3.25

the Fig. 3.26

the Fig. 3.27

a security loop (see fig. 3.26). It will tear at a glass razbivaniye, but if the thief uses стеклорез, can not work.

For protection on glasses widely use DIMK sensors let out by the industry (rice, 3.27). Such sensor is glued to glass and works on blows or a razbivaniye because the plate with the magnet fixed on it has no rigid fastening and at blows departs from геркона that breaks off a chain of a security loop (all sensors are connected consistently).

the Similar design is simple for making p independently or to get.

For the alarm system about blows and vibrations can be used by font also a V-2 type pyezosignalizator (BQ1, fig. 3.28) in common with the circuit of the amplifier.

This sensor is calculated on work in a range of temperatures ±60 by °C and is pasted to glass by glue or (fig. 3.29) nestles a metal plate on the car or garage case.

a Food of the circuit can be from 5 to 15 In, and sensitivity is established by the R8 resistor at control. At signaling device operation on an exit of the circuit there is quickly zero level. The device can be connected directly to the protection circuit (for example given on fig. 3.10).

On cars often apply sensors of mechanical fluctuations of the case to prevention of removal of wheels. Such sensor font>

the Fig. 3.28. The amplifier to a pyezodatchik

the Fig. 3.29. The type of fastening of the sensor

the cargo end (see fig. 3.30), but it possesses low reliability and demands frequent mechanical fine tuning of sensitivity because of a razbaltyvaniye, and also change of weather conditions.

Sensitivity of such sensor depends on roughness of a surface of the earth on a parking lot that quite often leads to false operations or uncontrollable decrease in sensitivity.

Fig. 3.31. The amplifier to the electromagnetic sensor

the Fig. 3.30. The sensor mechanical fluctuation

All these shortcomings is deprived by font the circuit with the electromagnetic sensor (fig. 3.31). As sensitive to to fluctuations of the sensor can be used small-sized миллиамперметр (for example from household radio equipment, М4370 and many other), having finished it according to fig. 3.32. For this purpose the case of the measuring device is opened and on the end of an arrow is fixed small грузик (it is possible to take a slice of tubular solder with internal rosin). Rosin is removed a needle, and the end of an arrow is inserted into the received opening and pressed out by flat-nose pliers.

At a choice миллиамперметра is unimportant, where it has an initial provision of an arrow — under the influence of cargo weight it will occupy average situation at the corresponding orientation of the device.

the Fig. 3.32 Design of the electromagnetic sensor mechanical fluctuation

Sensitivity of the electromagnetic sensor of fluctuations does not depend on roughness of a place, and it can work even from a light touch to the car, and its sensitivity is easy for changing the SP5-2B type R5 resistor (so, during a rain it should be lowered for an exception of false operations).

is better to apply two R5 resistors To convenience of operation and the toggle-switch to switch them on in advance established to sensitivity. The circuit of the amplifier it is better to dispose to a dagchik near the sensor.

For protection of a dark cellar or a cellar can use light sensor (fig. 3.33). He will allow to find penetration there the stranger who све^орл яавэрчяка will use.

Fig. 3.33. - lighting

the Resistors noted on circuits "*", it is required to select the sensor at adjustment.
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Sensors for the security alarm system

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