Cam secret online
"Assuming the camera has some form of lens, you use a device that has a very bright light source and a viewfinder that allows you to scan for the reflections from the lens," Professor Alan Woodward from the Center for Cyber Security at the UK's Surrey University, told CNN.
"If that were the case you could (assuming it's dark) turn off all the lights and use your forward-facing phone camera which tends not to have an IR filter fitted and so may see any IR illumination, assuming it's there.""If it does transmit RF, then you can again buy a standard bug detector that you sweep the room with to search for hidden sources of radio transmission," says Woodward.
Cameras are disguised as alarm clocks, power adapters, smoke detectors, photo frames and even water bottles, most of them wireless and battery powered.
These cameras are easy to obtain, and most require no technical skills to install, meaning anyone with ill intent could place them in a public place and watch you when you're unaware.
Of course, the fact that hidden cameras might be illegal doesn't stop people from placing them, so it's up to you to remain vigilant.Not that hotel guests are entirely immune from digital age privacy invasions.