Application of magnets in security
For the purpose of maintaining public
security, the Security & Protection System (SPS) applies
an intrusion alarm system, video security monitoring system, entrance and exit
control system, BSV liquid crystal joint wall system, access control fire protection
system, explosion-proof safety inspection system, etc. composed of security
products and other related products. Or an electronic system or network
composed or integrated by these systems for subsystems. The security system
mainly includes alarm system, monitoring system, control system, inspection
system, management system, processing system, command system, attendance access
control. Magnets are used by many security systems because of their unique
permanent magnetic properties, such as the door sensors, anti-theft magnetic
sheet, and traffic lights and intelligent traffic violation supervision and
management system:
1. Door sensor:
The door sensor is
used to induct the opening and closing of doors and windows, and its principle
is to use magnets to control the opening and closing of the magnetron. Door
sensors have one reed switch and one magnet, creating a closed circuit. If
someone opens an armed door or window, the magnet is pulled away from the
switch, which breaks the circuit and triggers an event. Depending on your setup
and what mode your system is in, this could be a discreet text, a chime alert,
or a full-blown alarm.
To avoid letting the
breeze or other natural causes start the door sensor, just install a second
magnet for extra flexibility with door and window positioning. That way the
entry sensor has two "safe" positions—say, "window closed"
or "window open 6 inches"—and if it's moved from either of those it
will trigger an alarm.
Of course, over time,
certain metals can affect the magnets within the sensors. If you are looking to
put an entry sensor on a metal object, a thin plastic buffer placed between the
metal and the sensor will ensure it remains unaffected.
As for its safety, the
intruder cannot use his own magnet to disable my door sensor, although
technically possible, this scenario is very unlikely. The burglar would need an expensive, powerful
magnet, and they'd need to know where the entry sensor is inside of the door.
If someone was going to do that, it would be someone who had already been in
your home and seen where things are. Even if a burglar tried, he'd likely trip
the alarm in the process, because reed switches are very sensitive, which
usually disturbs the magnetic field and causes an alarm.
2.Anti-theft magnetic sheet:
The anti-theft magnetic sheet is used for
car locks, which blocks the keyhole of the car physically, relying on its
strong magnetic force to attract the keyhole of the car lock, and cover the
lock core (closely connected) to protect the car.
The Anti-theft magnetic sheet has a strong resistance
to violence. If you use a screwdriver and a hammer to hit the device violently,
the device will be damaged, but it will not break. Due to the strong magnetism,
it will still be firmly absorbed in the keyhole. The polarity of the cracked
anti-theft device with strong magnetism is changed due to the fracture, the
mutual repulsive force will make the device to withstand the wall of the
keyhole, completely seal the keyhole, so as to achieve the effect of protecting
the car lock and preventing theft.
The main components of variable reluctance
pressure sensor are iron core and diaphragm. The air gap between them forms a
magnetic circuit. When there is pressure, the size of the air gap changes, that
is, the magnetoresistance changes. If a certain voltage is applied to the coil,
the current will vary with the air gap, thus measuring the pressure.
In the case of high magnetic flux density,
the magnetic permeability of ferromagnetic material is not stable, in which
case the pressure sensor with variable magnetic flux can be used to measure. A
variable permeability pressure transducer replaces the core with a removable
magnetic element. The pressure changes cause the magnetic element to move and
the permeability to change, thus obtaining the pressure value.