Q&A for How to Build a Hidden Camera Detector

Yes, but you'll need two of them. Download a red strobe light app on one phone and turn on a red strobe light. Then, turn on the camera on the other phone. Scan the wall with the strobe light while pointing the phone camera at it. If there's a hidden camera, you'll see a reflection in the phone camera screen.

Shine a flashlight on the spot you suspect. If there is a camera there, the camera lens will reflect the light.

If you are asking of they can see through walls, they can't. However, they may have heat sensing capabilities.

In some cases, yes, especially with motion-detection cameras. When you make a move in front of a motion-detection camera, it should make very soft buzz sound.

Use a different method because the spy could have changed their technology, hid the camera better or is only using audio now. If you really think you are being monitored again, you should leave or move.

That would depend on the size of your hard drive, the number of cameras on your system, and the resolution of your cameras.

You could try, but an unsaturated red light won't give any good reflection out of your camera lens.

If someone is living with you or has access to your house, they could hide a camera. If you live on your own, it is unlikely but possible.

First, take good photos of the entire area where the camera is located, just in case you need evidence later on. Then, if you trust that the local authorities are not involved in surveilling you, then call them to at a minimum come to your house and write a report of the camera. They'll more than likely take their own photos, too, as well as check for fingerprints or DNA, so try not to touch the camera or surrounding area(s). If the police do not collect the camera for evidence, then ask them if when they're finished with their crime investigation, if it is okay for you to remove said device. If so, then you can remove it.