Car Alarms

A car alarm is an electronic device installed in a vehicle in an attempt to discourage theft. Car alarms work by emitting high-volume sound (usually a siren, klaxon, pre-recorded verbal warning, the vehicle's own horn, or a combination thereof) when triggered or when circuit is breached.
Car alarms can be designed to be triggered by vibrations, tilting of the car (to prevent unauthorized towing), touching the car, the opening or closing of special switches (e.g. door contacts), sensing small but rapid changes in battery voltage (which might indicate an interior light going on, or the ignition circuit being activated), or using volumetric sensors such as ultrasound , infrared or microwave.
Many times a car alarm can be triggered accidentally. This may be caused by the passing of large trucks, the vibration of thunder or people coming into contact with the vehicle, triggering the alarm sensors. Some sensors may need adjustment in order to prevent false alarms.[citation needed]
Since many car alarms are triggered accidentally, most people in American cities are numbed to the sound of alarms, and do nothing to prevent theft. The New York City Police Department claims that car alarms are actually making the crime problem worse (see their booklet called "Police Strategy No. 5: Reclaiming the Public Spaces of New York," City of New York, New York, 1994) because nothing is done about the alarms, the general impression is that no one cares about the neighborhood.[citation needed]
Because of the large number of false alarms with car alarms, many vehicle manufacturers no longer factory fit simple noise-making alarms, instead offering silent—but effective—immobilizers.[citation needed] Alternatively, an aftermarket vehicle tracking system can enable the police to trace stolen vehicles. Most police tracking systems require the user to pay a recurring fee, whereas factory immobilizers are included in the purchase price of the vehicle. GPS locating systems enable the owner of the vehicle to lock and unlock, track, and disable the starter of the vehicle online. Other additional options allow the user to receive messages if the alarm is set off or if the vehicle breaches a specified speed or boundary. GPS systems are usually not paid monthly but locates are purchased. Both classes of devices deter someone from taking the vehicle without consent but do not cover them from theft, or vandalism of, the vehicle.
Yet another class of security covers aftermarket car alarms that include 2-way paging controllers. Two-way pagers have remote control functions built-in, allowing the user to arm and disarm the alarm while informing the user of threats made to the vehicle. Some 2-way systems have an LCD icon display that can pinpoint the actual part of the vehicle being threatened. Many two-way pagers can also alert the user with beeps or silent vibration.
Developed by a [los angeles car alarm company] is a newly released 2 way paging alarm that not only allows you to start your car remotely but also includes an in car camera that will snap a photo of the thief or intruder and instantly send his image to the remote pager.