That video can go to your smartphone, computer, or to a screen inside your home. Doorbell cameras are part of many home automated systems and provide an extra layer of protection. These cameras often come with two way talk, night vision, and a built in motion sensor. As with any security camera, check out the video resolution and field of view. When wireless doorbell cameras activate, the person outside your home will have no idea whether you are on the other side of the door or on the other side of the world. Door and window sensors are contact motion sensors that trigger an alarm when the protected door or window opens. Like stand alone motion detectors, these can activate when you’re away from home or whenever you choose. For example, you may keep the window sensors always activated but deactivate the door sensors when you’re at home. These sensors can function as part of your security system or on their own, and they vary in size and design from tiny, sleek sensors to bulky and obvious. Sensors also vary in sensitivity. Some may trigger when the door or window vibrates versus actually opening.