Researchers Build a Seven Dollar Tool That Finds Hidden Cameras

Researchers at KAIST have developed SweepLED, a hidden‑camera detection gadget that costs under seven dollars and attaches to any smartphone. Unlike traditional detectors that rely on spotting simple reflections, SweepLED sweeps LED light from multiple angles while the phone’s camera stays fixed, capturing how reflections deform across the sweep. Camera lenses have unique internal structures that produce distinct reflection patterns, allowing SweepLED’s AI model to identify them with 94 percent accuracy. The system records a short video of the sweep and analyzes it to flag exactly where a hidden camera may be located. In tests against 30 everyday objects found in hotel rooms and rentals, SweepLED detected cameras in under five seconds per item. This is a major improvement over consumer detectors, which a recent UCL study found miss 59 percent of hidden cameras. The project, led by Professor Jun Han and collaborators from Singapore, was presented at ACM MobiSys 2026 and could realistically become a commercial product due to its simple design. As hidden cameras continue appearing in rentals, hotels, and everyday objects, SweepLED offers a cheap and reliable way to protect personal privacy.

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