The main sensors react to the interventions on the car are:

CONTACT SENSORS
Each car has “buttons” factory assembled in the doorway. With their help the dome light turns on. These buttons are used to emit a signal to the alarm when some door is open. In the set of each professional alarm system are included two additional buttons which are assembled to the front and rear hoods.

 

SHOCK SENSOR
The shock sensor reacts to a hit of the car. There are two types shock sensors according to their physical principal of work:
Piezo-electrical
Magnetic-dynamic
Our alarm systems are produced with the both types of sensors. The peizo-electrical sensors are produced only to satisfy the market needs because they are cheaper. To work this sensor well it has to be assembled over a metal surface which gainsays to the secretion of the alarm system. It is needed to tune very often this sensor because of the temperature variation in Bulgaria and this takes time. Buy only alarm systems with external piezo-dynamical shock sensor!
Possible saving of money – Only the models VALCOR has system with external magnetic-dynamical shock sensor. Pay in addition 10 lv. to the alarm system.

 

VOLUMETRIC SENSORS
The volumetric sensors create a field in the car /single zone/ or in and out of the car /dual zone/.
The volumetric sensors increase the security level. They are not very precise and the false alarms are very often. If your car is cabriolet they are obligatory.
The volumetric sensors are two types according to their physical principle of work:
- Supersonic sensors – These are so called “eyes” on the both sides of the control board. The one of them is a loudspeaker, emitting a high-frequency sound and another is a microphone which accepts it. The sensor electronics reads the difference in the parameters of emitted and accepted sound /Doppler's effect/. If there is no difference the sensor is at rest. If there is some volume in the car the emitted sound reverberates in it and arm the sensor. The disadvantage of these sensors is that they make false alarms if there are some insects in the car and they alight on the “eyes”. Another disadvantage is that the warm and cold airs are different environment.
- Microwave sensors – They read the difference between emitted and then accepted reflex high-frequency radio-signal. If there is entering in the sensor radius the reflex radio-signal's parameters change. These sensors can function and outdoor the car and they are often dual-zone. Their disadvantages are: radio-frequency dependence; arming if the car is near a rocking tree or busy zones.
All systems of our firm /except CROTAL/ has an inlet for dual-zone volumetric sensors. The models VALCOR VR 52, 54, 72, 74 and 76 have such an inlet which is completely programmable and gives you an opportunity for different security modes and combination with the shock and volumetric sensors work and opportunity to switch them on and off irrespective each other.

 

SLOPE SENSORS
These sensors react to careful try to lift the car /for example jack up/ without the shock and volumetric sensors arm or in cases when they are disabled or non-assembled.

 

BROKEN WINDOW-GLASS SENSOR
This sensor reacts to the noise from broken window-glass. This type of sensor is very useful in case the car is at very busy streets which presumes turning off the shock and volumetric sensors.