A Layered Approach to Protecting Your Car and Its Contents

Directed Electronics, Inc./Viper Auto Security

It makes sense to build a security shield not just around your car, but also for your prized autosound system. Your first goal is to make it as tough as possible for someone to get inside your vehicle. Your second is to slow thieves down, throw obstacles in their path, maybe even page you when a break-in has occurred.

The keys to your first goal are a quality vehicle security system and the right sensors. Many vehicle security systems include circuitry often called warn-away. With this feature, a slight impact to your car results in a low-level "chirp" warning. A stronger impact triggers full alarm. Would-be thieves realize the vehicle is protected and, hopefully, move on to an unprotected car. This neighborhood-friendly feature also helps eliminate false alarms by responding differently to varying levels of shock or impact. Your neighbors won't hear a siren each time your vehicle is touched, accidentally or otherwise. Warn-away with trigger is available for use with most sensors. If triggered once, a quiet warning is issued; a second trigger within six seconds generates full alarm. If you prefer a verbal warning instead of the chirp, opt for a voice module. You can even record your own voice responses with a programmable voice module.

As for sensors, there are several kinds that can help protect your audio system. Shock or impact sensors are packaged with virtually every car alarm on the market. They trigger the security system if the car is hit with appropriate force. A two-stage is so smart, it decides whether to send the siren into full alarm (for heavy impacts), sound a warn-away signal (for lighter impacts) or nothing at all (big trucks driving by, etc.).

A field disturbance sensor responds when someone or something gets too close to your car. These also are called radar or proximity sensors. They work by creating an invisible field around your car. If someone breaks the field, the system will respond appropriately with a chirp, voice warning or full alarm. Your installer can set the signal's range from very close to several feet from your car.

Audio or glass-break sensors include a microphone and a processor that listen for the frequency of breaking glass. This type of sensor discriminates sounds and is very reliable. However, when installed in a convertible or a T-top, it needs to be turned off if the vehicle is left open. This prevents the sensor from hearing outside noises that may occur at the same frequency as breaking glass and activating the system.

Motion sensors are ideal if you think your car may be towed off by thieves. Basically, a motion sensor is a pendulum mounted in a tube. When it is tipped off-center, the pendulum hits a contact and triggers the alarm. Motion sensors also are good for sensing thieves' attempts to steal custom wheels.

An essential for any security system is starter kill, which prevents anyone from starting the car - even with your ignition key - after the security system is armed. But to really annoy anyone who tries to steal your autosound system, install a piezo siren somewhere inside the passenger area. This super-loud little siren is ear-piercing, and no thief will want to put up with it for long.

If you want to be notified whenever your vehicle security system responds to a threat, consider a pager. It will beep or vibrate when the system reacts; then you can decide whether to check it out or call the police. Some new pagers come with "intercom buttons" so you can give the pager to a passenger, drop him or her off somewhere like a mall, then page them to meet you upon return. Most pagers have a range of a mile or so - reception depends on the terrain, building and other interference.

If you're concerned that a thief might remove your car battery or cut its cables, get a backup battery. It will power your security system even it the main battery is out of the loop, and keep the thief frustrated. Just like your vehicle's main 12-volt battery, backups recharge themselves as you drive.

Finally, add pin switches for the hood, trunk, doors and anywhere someone might gain access to your system or its components. Pin switches trigger your system when these areas are opened. They're an inexpensive way to keep your car and its contents protected.

Always take the time discuss your security convenience needs with your dealer/installer. It can save lots of headaches after the sale.