Have you ever woken up in the middle of the night because a car alarm has been triggered and it won't stop beeping? An electric alarm system is meant to warn drivers when there is suspicious activity going on with their vehicle, but sometimes it seems like they can go off if someone looks at the car the wrong way.
Modern car alarms are complex systems of sensors and sirens that are designed to detect disturbances in a number of different situations. There are a variety of sensors involved in a security system that are designed to notice when the doors are opened, if the car is being loaded onto a tow truck and even if there is an unexpected increase in the level of noise nearby. In some cases, they can also detect if the car battery's voltage changes even slightly.
If any of the sensors are tripped, a signal is sent to the system's computer, which triggers the sirens to go off. Sometimes, the vibrations of a large truck or other rumbling engine can accidentally trip the sensors. If this happens often, or if the alarm is triggered when someone brushes up against the car, the sensors may need to be adjusted, as they are probably a bit too sensitive.
They can also be set off if someone tries to open a door or start the car. If you accidentally hit the lock button on the key fob before you start the car, the alarm will certainly remind you of your transgression when you turn the key in the ignition. Being caught inside your car when you trip the alarm can be deafening and rather unpleasant.
If you're nearby, it can be easy enough to stop it by walking to a window or stepping outside momentarily and pressing a button on the key fob, or remote control. This controller can also be useful if you forget where you've parked your car. Typically, pressing the lock button will trigger a beep of acknowledgment from the vehicle.
Car alarm systems are often customizable, and the sirens may come with a variety of alert noises to choose from. Some newer key fobs offer an LCD option that projects an image of the area of that car where the sensor was tripped.