Their are apps that can use your smartphone’s flash to light up camera lenses and help you detect hidden cameras. For iPhone, there’s Spy Hidden Camera Detector ($2.99); for Android, try Glint Finder (free, with advertisements). Hidden Camera Detector is a bit more helpful, as it automatically pinpoints suspected cameras on your phone’s screen. Glint Finder, on the other hand, flashes your smartphone’s light rapidly to make it easier to pick up a reflection, but it’s on you to find the source. With either app, you’ll need to be within a few feet of a camera to spot it.
The advantage of these apps is cost and accessibility. While you can purchase professional-grade camera detectors (more on those in a minute), they come with a notable price tag, while these apps are very affordable. And if you need to hunt for a camera unexpectedly, you’re likely to already have your smartphone with you.