A hidden camera is a still or video camera used to film people without their knowledge. The camera is "hidden" because it is either not visible to the subject being filmed, or is disguised as another object. Hidden cameras have become popular for household surveillance, and can be built into common household objects such as smoke detectors, clock radios, motion detectors, ball caps, plants, and cellphones. Hidden cameras may also be used commercially or industrially as security cameras.
A hidden camera can be wired or wireless. The former will be connected to a TV, VCR, or DVR, whereas a wireless hidden camera can be used to transmit a video signal to a receiver within a small radius (up to a few hundred feet).
Some hidden camera shows have led to lawsuits or being denied to air by the people who were trapped in set-ups that they found unpleasant.
