How Car Alarms Work and the Types that Exist

How Car Alarms Work and the Types that Exist

While not many people will find the need for car alarm systems, they’re still quite helpful. Of course, it won’t entirely stop any attempt at someone trying to access your vehicle, but it does help to deter it from happening. Anything from optical to acoustic warning can help chase away anyone with ill intent, which can activate when there’s a forced opening of the door, a hit, and the like.

That said, let us talk more about car alarms. Let’s talk about how it works, the type of car alarms that exist, and why you need to have one:

How Car Alarm Systems Work

The basic principle behind car alarm systems is pretty simple: it warns anyone who tries to force open or break into your car that they’ll be caught.

Now, this can be from a variety of methods from a variety of sensors. One of the most common features is the pressure sensor that goes in one of your windows, especially near the door. The sensor can sense when the glass is being forced, and thus the alarm is automatically triggered.

It can also be a shock sensor, which is activated when someone tampers with the car body. This can often be triggered by breaking the window, or at least by bumping into it.

Another method is the door trigger, which is more for vehicles that have a manual lock or are just difficult to break into. You can connect this to the central locking system so that it automatically arms the system once the doors are closed.

There are also engine immobilisers, where there’s a sensor that detects any abnormal wiring being plugged in, which effectively shuts down the engine. This method is mostly for luxury vehicles.

Types of Car Alarms

There are various types of car alarms, most of which are available in the market.

One of the most common types of car alarm is an auditory alarm. The usual range is about 200 meters, which is more than enough for your car to be within range. Even if the vehicle is parked in a busy parking lot, it can easily be heard. It can be loud or soft, depending on the car alarm system you get.

Optical alarms are also quite common, and they work like the auditory alarm, but it relies on light to get the job done. The light turns on when the car alarm is triggered. Some versions even have blinking or strobe lights to get your attention. This type of alarm is usually only effective within 50 meters, but it’s helpful in busy parking lots.

Shock sensors are a type of alarm that triggers when there’s movement or impact on the car body. Usually, this is the window or the door, although the trunk could also be subjected to this. Many car alarm systems already have this integrated, so if your car alarm system already has one, there’s no need to buy another one.


So, do you need a car alarm? The answer is it depends. If your car is parked in an area where there are lots of people walking by, it’s not necessary. But if you know you’ll leave your vehicle in a parking lot or side street somewhere, it helps to have one. It’s all about preventing crime. There are other ways to help prevent crime, but if your car doesn’t have an alarm, why not? All in all, car alarms are still quite useful, especially if you park in high-risk locations.

Vehicle Security & Electrical is Yorkshire’s number one provider of vehicle security and electrical systems. If you need car alarm systems in the UK, check out our products!

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