Hidden camera detector - Electronic Device Detector is an application that is very easy to use and that provides a very good service. It can be used to detect hidden cameras and microphones in your surroundings. It works by measuring the magnetic field level in your surroundings. The app uses the magnetic field sensor of your phone to measure the level of the magnetic field in your surroundings. If there is a change in the magnetic field level, then there is a presence of a hidden camera or microphone in your surroundings.