The first mentioned car theft happened in 1896, only ten years after cars were first introduced. Since that time cars have become a natural target for thieves because of their value, reasonable resell easiness and a built-in getaway system. According to the statistics, a car gets broken into every 20 seconds in the United States.

Therefore, it’s not
surprising that millions of Americans have invested in expensive alarm systems. Nowadays huge amount of cars are equipped with some complicated electronic sensors, sirens and remote-activation systems. These alarms make the cars fortresses on wheels! Modern car alarms are extremely elaborate, and it's very remarkable that thieves still find a way to steal cars.

If you need a simple car alarm, just get one or more sensors connected to some sort of siren. The simplest alarms have a switch on the driver's door, wired so that if someone opened the door the siren would start making noise. You can make this alarm with a switch, some wires and a siren.