An immobilizer is an anti-theft device that does not reveal its presence to an intruder. Modern devices have a contactless control system that prevents hijackers from scanning the signal.
Immobilizer - a device installed in a car to prevent theft. Like the alarm, it deprives the car of mobility, but unlike the latter, it does not give out its presence to the intruder. A key fob, sensor or tag is used to activate the device.
Types of devices
The activation of many types of these devices occurs when the driver's door is opened. If the block does not read the label, then the engine will stall after a while. The most widespread are sensory and tag-activated immobilizers. All other types are either rarely used or have ceased to meet modern anti-theft requirements. These are coded devices, either those that are opened with a coded key, or biocode devices that require a fingerprint scan.
Immobilizer device
1. Control unit.
2. Relay blocking. The most effective are digital blocking relays. They do not communicate directly with the main unit, but interact using a radio signal or standard wiring. The latest generation systems operate at 2.4 Hz, which makes it impossible for hijackers to scan the signal. However, in some devices, the main unit is combined with a relay.
3. Touch sensor, label or key. Having removed the main unit or expelled the owner from the car, the hijacker will still not be able to leave on it - the car will remain motionless, because after a short period of time the blocking relay will close the required circuit. The main interlock circuits include the fuel pump, ignition, injectors and starter.
Some drivers have already appreciated the novelty of the car security system - an immobilizer with contactless control of the system. In such a car, the antenna is hidden under the interior trim, and the control is carried out by means of a card or key fob. As soon as the owner of the car brings the key fob to the hidden antenna, the system will disarm and unlock all circuits. If the control is carried out by means of a card, the driver does not need to do anything at all, the main thing is to take the card with him, and the system “recognizes” its owner using it. Naturally, the signals received by the card and the key fob from the antenna are encoded, and the transponders themselves are "eternal", that is, there are no batteries in them.