Motion detectors are designed to be your last line of defense. If an intruder manages to get past your other sensors, they cannot escape the motion! A Motion Sensor is a vital part of every basic security system so that you can know that your home is safe, even when you’re not around. The device is “pet immune” preventing false alarms in homes with animals. This way you can make sure that both you and your furry friends are always protected. By adding a Motion Sensor to your home security system you can cover large open portions of your home with one device.