Counter-Surveillance & Privacy Law

The other side of the catalog: RF detectors, lens finders, and how to check a rental, a car, or your own home for devices someone else planted. Plus plain-English guides to recording and tracking law.

The honest starting point is that an RF detector cannot see a camera that is not talking. A large share of hidden cameras record to a card and transmit nothing at all, and several of the ones that do transmit only wake up in short bursts when motion triggers them. A detector swept through a room in ninety seconds can pass a metre from a live device and stay silent. It is a useful instrument for the devices that stream constantly, and useless for the rest, which is why nothing here is sold as a guarantee.

Lens finders work on a different principle and have a different blind spot. A ring of red LEDs around a viewing hole returns a bright retroreflection from a glass lens, which is genuinely effective at close range and in a darkened room, and which also lights up screw heads, smoke detector housings and the shiny plastic on a television. The method rewards patience: slow passes, low light, and eye level changed twice.

What actually finds devices is procedure rather than gear. Power sources first, because a camera without a battery needs a cable. Then the objects that face a bed or a shower, then the ones that were not in the room yesterday.

If you find something, the useful move is to photograph it in place and contact the police rather than pull it apart, because a device removed and opened is evidence nobody can use. Nothing on this site is legal advice, and the rules on recording and tracking differ by country.