Car alarms became a popular mechanism for deterring vehicle theft beginning in the 1970s and 1980s. No one knows for sure who invented the first car security system, but, according to some sources, a Nebraskan man created the first alarm system back in 1920, well before they gained popularity. When first introduced to consumers for mass consumption, car alarms usually consisted of a siren that would go off when a device connected to it triggered by a person was trying to enter a vehicle without authorization.
Cars have always been highly susceptible to theft, thanks to the ease with which they can be transported from the crime scene, and then resold for an often substantial profit. Approximately every 20 seconds, a car is stolen, so car security of some sort is a necessity, particularly when one lives in a busy, large city.
A car alarm system hooks up to the battery of the vehicle, but usually has a back up battery, in case a thief cuts the main power wire. The main components of a car alarm usually consist of a keyless entry remote, which communicates with a radio receiver placed in the vehicle to disengage and engage the car alarm system. Sensors involved in car alarms can include a shock or pressure sensor, motion detector, and switches incorporated into door, trunk, and hood latches. A small computer controls it all, activating the sensors when a possible break-in occurs. If an owner sets their car alarm shock or motion sensor at too high a sensitivity level, false warnings can occur from something as simple as a passerby stepping too close to the vehicle, or fireworks going off nearby rattling the windshield. This is why it is important not to set the car alarm system at too high a sensitivity, and to ensure you install it correctly into your vehicle.