As a society, we've accepted that security cameras are everywhere in public. But inside hotel rooms or AirBNBs, we still have an expectation of privacy. In 2024, there were some 75 lawsuits against AirBNB filed by guests who discovered they had been secretly recorded by their hosts. The platform subsequently banned hidden cameras, but detection and enforcement remain tricky.
Researchers at KAIST (the Korea Advanced Institute of Science and Technology, something like South Korea's MIT) have developed an inexpensive way to detect hidden cameras using your smartphone. The researchers built an LED rig (reportedly costing $7 in parts) called SweepLED that attaches to your phone. You turn it on and sweep the room, with the intention of getting the LEDs to return reflections from glossy objects.
While all glossy objects return reflections, camera lenses, due to their optical construction, return a particular type of reflection. The researchers used AI to train software to recognize these lens reflections and flag them. In their testing, the SweepLED device detected hidden cameras with 94% accuracy.
The team has not announced any plans to commercialize their invention. They should; with a BOM that low, I imagine these would sell well and be hugely profitable.