Are Small, Hidden Security Cameras Legal?
Yes, with some conditions. Monitoring your home with exposed or hidden cameras, even without a visitor’s consent, is generally accepted as a personal right. No federal statute outlaws either act, and plus, police in multiple states have used home video evidence to pinpoint suspects (who probably didn’t know they were being filmed), not to arrest the victims for recording crime in the first place.
That said, it’s illegal nationwide to place a camera, exposed or hidden, anywhere that person should have a reasonable expectation of privacy: for example, in the bathroom. And in some states, it’s illegal to record audio in any context and with any device, including a video camera, without the other person’s permission.
In the end, state and federal laws around small hidden security cameras for homes suggest that intent matters a lot. If your goal is truly to secure your property and family, not entrap someone or violate their privacy, your hidden camera probably gets a thumbs-up.