"Not sure....bought the barking alarm that senses motion through the wall and it barks with nobody outside. Not sure what is triggering it and it can get loud and annoying with all the false triggers....sounds like a real dog. If it is defective and can be fixed...it would be a great device."
Does a Motion Sensor Dog Barking Alarm Really Work? | 1800Doorbell
On the outside, all devices look the same but on the inside, they use different sensors to perceive movement. When barking dog alarm like rex barking dog is using radar technology it is emitting radio waves similar to those in a microwave. It then senses reflection getting back to the sensor and if reflecting waves are changing, then dog alarm knows something is moving. On the other hand, we have devices like Doberman Security SE104 model that is using PIR sensors. PIR stands for Passive Infrared technology. PIR sensors are monitoring infrared radiation such as temperature and are looking for changes in the environment. When stationary no alarm will be triggered, but when moving barking sound will be played.
Barking Dog Alarm - Guard Dog Defense
"I had originally tried another dog alarm (Rex) from another company but its range was not as good as this one. In my home, the best place for the dog to detect motion was on the floor at a 45 degree angle to the wall back of the unit facing the patio. That worked better than in front of the windows which have metal. That bark would scare anyone."
Barking Dog Alarm - Home Security
This is why any advertisement that you see for a barking dog alarm
will stress that these alarms give you the security advantage of owning a
dog without any of the disadvantages. So it again comes down to whether the dog bark alarm sounds authentic
or not. If it does it will likely deter a good many burglars,
particularly On the other hand, a siren alarm may be better at attracting the
attention of passers by. The sound of barking may be just an ill trained
dog locked in the house.
Protects your home, garage, shed or caravan 24 hours a day!
A barking dog is one of the most effective deterrents for keeping burglars away from your home. This barking dog alarm, gives you the same level of security without the commitment or responsibility of owning a dog. Providing an effective deterrent when you are not at home, and an audible alert convincing others of a canine companion when you are, it uses radar technology to detect intruders through doors, walls and windows. Once triggered it gives out the sound of a vicious barking German shepherd dog protecting your home 24 hours a day. If desired it can be set to sound an alarm sound instead to let you know when anyone is approaching your door. Operated by AC adaptor 6 x AA batteries.