A wireless camera may or may not be truly “wireless.” Although some are powered by batteries, many actually need to be discretely plugged into the wall or otherwise attached to an electric system. They do use wireless transmission, however, which means that you do not have to run a cable from the camera to the receiver. This can make them more convenient to use and easier to hide.
Detecting the Image
A wireless hidden camera creates pictures like any other digital video camera. Light comes through the lens, which focuses it on a small grid of light detectors. In a black-and-white surveillance camera, each detector simply gauges how much light there is at a particular place in the image. In a color camera, each detector only measures red, green or blue light, and then groups of three detectors are combined to show the color of light in a particular place. All of these individual photo detectors are then combined to make a complete picture. Some wireless hidden cameras also have a motion detector and a motor that automatically makes the camera follow any movement in the room. Other cameras just continue to focus fixedly on the same spot.