Level 1 - Absolute Beginner

Scientists made a small tool for phones. It can find hidden cameras.

The tool is called SweepLED. It costs less than seven dollars to build.

The phone's camera stays still. A small light on the tool moves and shines in different directions. A computer program looks at the light and finds the hidden camera.

It works fast. It can check one object in less than five seconds, and it is right about 94 percent of the time.

hidden camera

a small camera that is placed secretly to record people without them knowing

gadget

a small tool or device that does a useful job

attachment

a small part added onto another device

LED

a small light that uses very little power

reflect

when light bounces off a surface

AI

a computer program that can learn and make decisions

accuracy

how often something is correct

prototype

an early version of a product used for testing

Level 2 - Elementary

Researchers at KAIST in South Korea, working together with the National University of Singapore and Singapore Management University, have built a cheap smartphone attachment that can find hidden cameras, for example in hotel rooms or short term rentals.

The device is called SweepLED. While it checks a room, the smartphone's own camera stays completely still, and only the direction of the attached LED light changes as it sweeps across an object.

An AI program then studies how the light reflects off the object's surface. On normal objects, the reflected light moves around or disappears as the light direction changes. A hidden camera lens reflects light in a very different pattern, so it stands out clearly, even when the hidden camera itself is turned off.

In tests on 30 different kinds of objects commonly found in hotel rooms, SweepLED reached about 94 percent accuracy, and checking a single object took less than five seconds. The core parts of the device cost less than seven dollars, and while it is still a research prototype, the team believes its low cost could make it suitable for commercial production.

attachment

a small device connected to a larger one to add a new function

sweep

to move something steadily across an area, side to side

reflection

light that bounces back off a surface

surface

the outer or top layer of an object

pattern

a way that something repeats or is arranged

commonly

in a way that happens often or is usual

commercial production

making a product in large numbers to sell to customers

core component

a main part of a device that is necessary for it to work

Level 3 - Intermediate

A team of researchers at KAIST, the Korea Advanced Institute of Science and Technology, collaborating with colleagues at the National University of Singapore and Singapore Management University, has developed a low cost smartphone attachment designed to detect hidden cameras in spaces such as hotel rooms and short term rentals, where covert surveillance devices are an increasingly reported concern.

The system, named SweepLED, takes a distinctive approach to the problem. Rather than relying solely on the smartphone's own camera to scan a room, the device keeps that camera fixed in place while changing only the direction of an attached LED light as it illuminates surrounding objects. An AI model then analyzes the resulting patterns of reflected light.

On ordinary surfaces, reflections shift position or fade as the angle of illumination changes. A hidden camera lens, by contrast, produces a distinctly different reflection pattern that persists across the sweep, allowing it to be identified even when the concealed device is powered off and emits no signal of its own.

In evaluations across 30 categories of objects commonly encountered in accommodations, the system achieved approximately 94 percent detection accuracy, with each inspection completed in under five seconds. According to Professor Jun Han, who led the research, hidden cameras pose a serious threat to personal safety and privacy in everyday spaces, and the project's significance lies in combining inexpensive smartphone based hardware with AI analysis to offer a practical detection method that even non experts could use. The core LED attachment currently costs under seven dollars to build and remains a research prototype, though the team argues its low cost positions it well for eventual commercial manufacturing.

covert surveillance

secret watching or recording of people, often without their knowledge or consent

illuminate

to light up or shine light onto something

distinctive

clearly different from others, easily recognized

conceal

to hide something so it cannot be seen

evaluation

a test or study used to judge how well something performs

detection accuracy

how often a system correctly identifies what it is designed to find

non expert

a person without specialized training or professional knowledge in a field

manufacturing

the process of making products, often in large quantities

Level 4 - Advanced

Researchers at KAIST, working in collaboration with the National University of Singapore and Singapore Management University, have introduced a strikingly inexpensive smartphone attachment aimed at a persistent and unsettling problem: the covert placement of hidden cameras in hotel rooms, short term rentals, and other spaces where guests reasonably expect privacy.

The device, called SweepLED, departs from the intuitive assumption that detecting a hidden camera requires scanning a room with the smartphone's own lens. Instead, the phone's camera remains fixed throughout the process, while only the illumination direction of an attached LED changes as it sweeps across surrounding objects. An AI model is then tasked with interpreting the resulting reflection patterns, an approach that sidesteps the unreliability of trying to spot a lens by eye or by relying on a camera detector to pick up a signal that a well concealed or powered off device may not even be emitting.

The underlying logic exploits a physical asymmetry between ordinary surfaces and camera optics. As the LED sweeps, reflections from most household objects shift position or fade entirely, whereas a camera lens produces a comparatively stable and distinctive reflection signature that the AI model can isolate, even when the device generates no electronic signal of its own. Evaluated across 30 categories of objects typically encountered in accommodations, the system achieved roughly 94 percent detection accuracy, with each inspection requiring under five seconds, a combination of speed and reliability the researchers argue distinguishes it from existing detection methods that demand specialized equipment or trained operators.

Professor Jun Han, who led the research, framed the work's significance in terms of accessibility as much as performance, saying that hidden cameras pose a serious threat to personal safety and privacy in everyday spaces, and that the research is meaningful in combining low cost smartphone based hardware with AI analysis to present the possibility of a practical detection technology that even non experts can use. With its core components costing less than seven dollars, SweepLED remains, for now, a research prototype rather than a commercial product, but the team contends that its minimal hardware cost leaves it well positioned for eventual mass manufacturing, a prospect that would meaningfully lower the barrier to camera detection for ordinary travelers rather than leaving it to specialized security services.

covert

done secretly, not openly acknowledged

intuitive assumption

an idea that seems obviously true without needing proof

asymmetry

a lack of equality or balance between two things being compared

optics

the components of a device, such as lenses, that deal with light

signature

a distinctive pattern that identifies something