Development of the Car Alarm
- Even many early autos came equipped with car alarms.Image by Flickr.com, courtesy of anyjazz65
According to an article in Popular Mechanics on June 20, 1920, a Nebraska inventor created an automobile-theft alarm. The following quote explains the alarm system: "A friction gear, thrown into or out of engagement with the shaft by a cam, is enclosed with the alarm in a riveted steel case, fixed to the shaft housing and radius rods. The cam also short-circuits the magneto, so that turning the key in the lock stops the engine and sets the alarm. The lock is located in the floor of the driving compartment." - In the late 1970s and into the 1980s, car alarms consisted of a device that created a siren sound when an unauthorized person tried to enter the car. The loud, screeching sound is annoyingly well-known to most people in the United States.
- Car alarms are based on several different technologies.
An active car alarm works by clicking a transmitter that turns a sensor on or off. When the alarm is triggered, it stops certain functions of the vehicle such as the ignition, fuel circuits or the starter.
A passive car alarm activates automatically when the engine is turned off and when the doors are closed. In some systems, the alarm turns on the dome light and locks the wheel jack, which prevents tire thefts.
An immobilizer locks the starter and ignition functions when something other than the key is used in the ignition. These systems sometimes lock the doors and engage the emergency lights. The immobilizer sensor can also detect contact on the outside of the car.
The two-way alarm has a two-way radio control. One is placed on the vehicle, while the owner has the other. When a theft is detected on the device, the owner can initiate an alarm. This technology is evolving with the use of liquid crystal display (LCD). - For every anti-theft device created, it seems there is a workaround for ingenious thieves. A car is stolen in the U.S. every 26.4 seconds, according to the FBI's Uniform Crime Report. One in 200 cars is stolen.
- Alarm systems are sure to evolve, but the trend is more toward silent systems, as many cities are pushing for ordinances against sirens and their high level of noise pollution.
