bilalarm

A bilalarm, literally “car alarm” in several Scandinavian languages, is a vehicle security device designed to deter theft and alert owners to tampering. They are commonly installed as aftermarket systems but may also be factory fitted as part of a broader anti-theft package.

A typical bilalarm consists of a control unit, one or more sensors (door switches, shock or impact sensor, tilt or movement sensor), a siren or horn, and power supply. Many modern units also include a remote key fob, a dashboard LED, and optional smartphone connectivity or GPS tracking.

When a sensor detects unauthorized access or movement, the system triggers an audible alarm, flashes lights, and notifies the owner via a mobile app or a remote receiver. Some alarms include an engine immobilizer that prevents starting the vehicle until authentication is restored.

Alarms come in various forms: basic audible alarms only, alarms with immobilizers, and advanced telematics systems that provide location data, geofencing, and remote arming/disarming. Aftermarket bilalarm devices vary in features and stealth; factory-installed systems are commonly integrated with other vehicle security features.

In terms of security and practicality, while alarms deter theft and aid recovery, modern thieves may employ techniques to bypass certain alarms; therefore many systems use multiple sensors and encryption. Vehicle insurance often offers discounts for equipped anti-theft devices, but local regulations regarding nuisance alarms may apply.

See also immobilizer, vehicle security, telematics.