Spy devices aren't just for James Bond; a wide variety of spy equipment is available on the open market. Spy devices are used by law enforcement agencies, intelligence personnel, private detectives, and even everyday citizens. There are many different spy devices, including surveillance products, such as bugs and cameras, and anti-surveillance devices such as signal scramblers.
Surveillance equipment helps monitor activity through a method that is not detected by the subject. This means that most surveillance technology is quite advanced, as it must be able to pick up activity while being small enough to overlook or mistake for something else. Some spy devices, however, rely on tricks instead of technology; a simple one-way mirror is identical to a regular mirror from the subject's side, but is as transparent as a window from the surveillance side. Many stores use one-way mirrors to keep an eye on potential shoplifters or register robbery.
Cameras are one of the most popular surveillance devices, popular in thriller films but also quite useful in real life. Spy cameras may record video or still images, and can even be disguised as other objects. Pens, clocks, and doorknobs are all common devices that can be used to hide cameras. Some security systems prefer to use surveillance cameras that are visible to targets, to make it clear that actions are being monitored. Some stores will even erect fake security cameras to create a greater sense of security than actually exists.
Cameras are excellent for capturing images, but do require a clear field of view that can limit their flexibility. Some spy devices, often called bugs, are small recording devices meant for picking up conversations. Spy microphones can be unobtrusively dropped almost anywhere; one popular cliché involves hiding a microphone in a floral arrangement. Many modern cameras use wireless technology that transmits the recorded information to a remote station for the spy to hear. Another form of conversation recording, known as tapping, uses an additional electric circuit or a digital switch to transmit phone call conversations to a third party.
With so many spy devices around, it is only natural that a large anti-surveillance market also exists. This includes a wide variety of detectors that can pick up on the frequencies emitted by hidden microphones and cameras, allowing the target to know if his or her location is under surveillance. The spy and anti-spy industries play a continual game of cat-and-mouse, with each trying to trump the other's newest innovations.