Home Security Systems and Pets
I wont go into great detail about how pet immune home security system motion detectors work, however will tell you they operate off dual beams and they must both be hit simultaneously to violate the security system sensor. Chances are even most large dogs arent big enough to set the motion detector off. One word of caution is that if you have multiple pets there is a chance both may hit the different beams simultaneously setting them off which of course would trigger the alarm system. Because of this many professionals in the home security field dont recommend motion detectors staged at places where they may be set off by multiple pets roaming within the house.
Dogs and security systems are one of the best ways to increase your overall home security.