Which Alarm Sensors Work Best?
Whether you are subscribing to a professional home security service or building your own home security network, you have a wide variety of sensors at your disposal to help keep things safe.
Motion sensors do exactly what their name suggests. They can be placed inside the home to look out on an entire room, or outside the house to protect a driveway, front porch, or other sensitive area. The radius and range varies, but a typical interior motion sensor covers a 90-degree radius and reaches 30 feet across a room.
Some systems feature motion sensor cameras that record images and also set off an alarm if something moves. Many of these can even be set to ignore small, low motions like those of a pet cat.
Magnetic Contact Sensors
Most commonly used on doors and windows, these sensors connect a circuit via a magnetic connection. One pickup will be mounted on the window and the other on the frame (or in the case of a door, on the door and the jamb). When the window is slid shut, the sensors are within a couple inches of one another and the low-voltage current connects, but when the window slides open the circuit is broken, causing the alarm to trip.
According to the Washington Post, 85 percent of burglaries involve unauthorized entry through external doors or first-floor windows, so contact sensors serve as the primary burglar alarm sensor.
Sometimes these sensors are wired directly to the control panel or to one another, but other, newer systems use wireless sensors. Another contact sensor tip? Make sure you secure the door from your garage to your house, as an open garage door is an invitation to burglars, and many garage doors are easy to hack.
And if you don’t have a home security system but still want to secure your doors while you are at home, consider the Door Stop Alarm, a nifty $10 device that sounds a loud alarm if the door swings open. (This also works great in hotel rooms.)
Glass Break Sensors
Magnetic window sensors only alert you if the burglar slides your window open. However, they can protect you against the thief who breaks your window by sensing vibrations and knowing what to listen for. Many glass break detectors can hear a shatter sound from up to 25 feet away, so even if the window is across the room, the detector will recognize the frequency and set off the alarm.
The best approach is a varied one. Use door sensors, window sensors, and motion sensors in conjunction with one another. And most of all, the mere fact that you have an alarm system is great: according to the Washington Post study cited above, a house without an alarm system is three times more likely to be robbed than one with a security system.
Photoelectric detectors create an invisible “trip wire” by aligning two sensors at a variable distance. These work just like the sensor at the bottom of your garage door that keeps people from getting crushed, except that when tied to a security system, a tripped wire causes an alarm.
These sensors are less effective than many others, because a wary thief can simply step over or under the invisible beam. If you can install it somewhere out of sight, like tucked away in bushes on either side of a driveway or front porch, you may catch a crook.