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Auto mobile central locking system

spaceage security systems

Such systems protect the cars or similar vehicles from theft. There are different kinds of locking system available in the market using various principles.

The most common locking system gets activated when any of the doors of the car is opened. On each door a micro switch is fixed (if central locking is not already there). Once any door is opened the switch of that door gets activated which in turn activates the alarm. In some of the versions that are available in the market, the alarm will go on for 90 sec., after which it will automatically stop. The advantage of such feature is that if the alarm is unattended the battery does not get drained off. In some countries this is mandatory that alarm must switch off automatically so that it does not endlessly disturb the neighbors. Some of the systems offer additional protection upon activation like cutting of the engine or cutting of the fuel supply etc.

Another type of automobile alarm gets activated when there is an impact on the car. Such impact happens if someone breaks the glass or the car is physically towed away or someone tries to open the door with force. The advantage of such a facility is apparent but there are disadvantages too. One of the major disadvantage is that such alarms go off accidentally even if someone leans on the car. Some of the systems are so sensitive that if truck passes close by, the impact of the air can activate such an alarm. Such alarms are quite cheap but lead to lot of false alarms and cause inconvenience to the owner and the neighbors alike.

To overcome such disadvantages the advanced alarms use ultrasonic sensors. In such systems the ultrasonic transmitters transmit the ultrasonic (high frequency sound waves) waves which form a pattern in the car by getting reflected from various surfaces. The ultrasonic receiver receives the ultrasonic rays indirectly after getting reflected from many sources. If a door is opened or a glass is broken then this pattern of waves gets altered and the receiver does not get the expected intensity of the ultrasonic waves. When such change is detected the central unit then takes the predefined action which can be sounding of alarm or cutting of the fuel supply etc.


To activate or deactivate the alarm there are two common methods. First (the obsolete one) is the key pad based system in which owner has to key in his password with in a specified time after getting in the car. Such a system is inconvenient as switching on or off of the alarm requires certain time.

The second way to activate or deactivate the alarm is by using a remote control. The remote is smaller than a match box and uses a predefined code while transmitting information to Receiver. This code is unique for each car. Due to this unique code, remote from different cars do not interfere with each other. There are thousands (and even millions) of such code combinations, depending upon the technology used by the Remote manufacturer. The code is set by the manufacturer, in the hardware (IC) of transmitter and Receiver. So, if you loose your Remote, you may not be able to get another one readily from the dealer.

While the security systems are improving the thieves are also getting technology savvy. In some advanced countries, the thieves use special equipment to decipher the electronic code that the transmitter transmits to open or close the car. To beat this loophole, the more advanced remote use a hopping code. By using a hopping code the code is changed automatically every time the remote is used . This system is useful to defeat thieves who may use electronically advanced gadgets to track the codes.

In still advanced systems once the alarm is activated it activates a pager/beeper which is carried by the owner. The range of such remote is around 250 meters. The biggest advantage of such pager based system is that user gets alerted every time the alarm is activated in the car. Otherwise it has been seen that the alarms keep on going off in parking areas, but the owners are unable to hear inside the house or in the office.

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