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ADT® Motion Sensors: What You Need to Know

Most security system packages, including those offered by ADT, come with motion sensors. These sensors can help secure your home, but many people don’t understand how they work. Here are the answers to a few of the most common questions about motion sensors.

Why Do You Need Motion Sensors?

If your home has more windows than average, motion sensors could be a great option for you. Motion detectors help secure an entire room with just one sensor, saving you money and simplifying installation by reducing the number of sensors you need to help secure your home.

How Do These Sensors Work?

ADT monitored security systems use passive infrared sensing technology, which doesn’t require any emitted signals to sense movement. Instead, these sensors rely on the infrared energy given off by any heat source with temperatures above absolute zero, or -459.67 degrees Fahrenheit. Motion sensors are sensitive in the 8-12 micrometer range of infrared energy, which is the range that corresponds with the temperature of human skin, about 93 degrees Fahrenheit.

Motion sensors detect changes in infrared energy, but only if the change is rapid. For example, if someone walks past a motion sensor it will pick up the change in energy and trigger the alarm.

Heating and cooling your home won’t trigger an alarm because the change in energy is too slow. Sensors also won’t pick up motion outside a window because the infrared energy cannot effectively penetrate glass.

Can Pets Trigger Motion Sensors?

Many homeowners are concerned that their pets will accidently trigger motion sensors, but advances in technology have solved this problem. Modern motion sensors can detect the approximate mass of a moving object, and sensors are available with either 60 or 80 pound weight minimums needed to trigger the alarm.