A hidden microphone is a device designed to pick up voices and other sounds while remaining out of sight. For example, a hidden microphone may be embedded in a pen, item of clothing, piece of furniture, or electronic device that isn’t normally used for picking up sound. Some hidden microphones are even designed for use in flower arrangements. Often, though not always, hidden microphones are used in combination with hidden cameras, allowing the user to hear and see events in the area without alerting others.
Talk of hidden microphones often brings images to mind of people spying on each other, but these microphones aren’t always used in that manner. They may be legitimately used on TV shows that have a host who needs to remain mobile, for example. In such a case, a hidden microphone allows a TV host to move about as much as necessary and speak to his audience no matter where he goes on the set.
Sometimes a person may use a hidden microphone to record the details of his own conversation. A journalist may use a microphone pen, for example, to record the details of an interview and retain information provided off the record. Another party may use a hidden microphone to record another person’s admission of guilt or threats.
There are also many ways in which hidden microphones may be used as spy equipment. For example, an individual may suspect his spouse of adultery and install a hidden microphone to record what she says while talking on the phone. He may even set one up to record what happens in their bedroom while he’s away from home. A parent may place such a microphone in his teen's bedroom in order to learn what he says in private conversation. An employer may even install a hidden microphone to eavesdrop on what his employees are saying throughout the day.
It’s important to note that many jurisdictions make certain uses of hidden microphones illegal. In many places, it is illegal to record phone conversations without asking permission, even if the person is recording his own spouse. Placing a hidden microphone in another person’s home, office, or private space may be considered illegal as well. On the other hand, law enforcement officials in many jurisdictions are permitted to use hidden microphones to solve cases and record confessions, but they typically have to secure a court’s permission to do so.