Our purpose of writing this article is to let people who travel a lot have an understanding of the working principle and working environment of hidden cameras, so that they can quickly detect potential hidden cameras in some hotels and protect their privacy from being violated by others.
Note Sunba Technology sells professional outdoor Pan Tilt Zoom cameras for 7*24 hours continuous monitoring, which is different from hidden cameras in terms of size (4~6 inches) and structure. But the fundamental working principle of all surveillance cameras are similar. This article is aimed to briefly introduce the working principle and working environment of the hidden cameras.
With the development of science and technology, clandestine surveillance is desirable in many sites with limited space such as banks and museums etc. However, there appears to be increasing reported cases of found hidden cameras in hotels, even in airbnb, especially in some Asian countries. This has also become a major concerns for some of our employees during travel. If you do not pay attention to this, your privacy might be exposed, and the captured videos might even be sold for profit.
1. Structure of Hidden Cameras (aka. Spy Cameras)
Hidden cameras are extremely small. Some of them are even pinhole size. They are usually equipped with small focal length with a wide-angle fisheye lens that can monitor the entire room.
Hidden cameras are often camouflaged and concealed on electrical equipment facing the bed (such as televisions, air conditioners and chandeliers). Generally, they needs to be installed close to a power source (except for those with lithium batteries).
2. How to Detect Hidden Cameras?
A. Scanning Apps
The scanning apps can quickly identify all online devices in the network. However, this method is only applicable if the devices are connected to local network. Many equipment are using 4G/LTE network or are offline with local storage.
You can download and install “Hidden Camera Detector” app.
You can also use desktop web scanner such as “Advanced IP Scanner” to see if there are unexpected equipment on the network.
For this method, even if you have detected potential hidden cameras, it might not be installed in your room so it is recommended to check/verify with hotel manager with the mac address captured.
B. Check Infrared LED
This method is applicable only for hidden cameras with infrared LED at night vision mode.
You can turn off the lights in the house, close the curtains, turn on the recording mode of the mobile phone, scan around the house to check whether there are red/purple dots, or signal light that is flashing (some long-wavelength infrared rays cannot be captured by the human eye but only with the smartphone’s CMOS).
Again, many spy camera manufacturers have removed the infrared LED from their products so this method might not be as effective as before.
PS: If you use smartphone, make sure it doesn’t have IR filter. Some new models have IR filter which will not show red dots for coming infrared LED. There are also dedicated infrared detectors.
C. Detectors
Most detectors are just flashing LEDs (with batteries) that is used to detect reflective lens. So you should be able to use a flashlight with equivalent results.
You can turn on and move the detectors closer to where the hidden cameras might be present. A detector utilizes the reflection of the CMOS sensor on the lens focal plane, which will reflect back the original flash after being refracted by the lens. In other words, if you see reflections on the viewfinder on the detector, it is most likely a camera.
In fact, the effect of a flashlight is the same, just make sure the flashlight is close to your line of sight.
D. Check Common Areas and Common Devices
The areas that are most likely to hide pinhole cameras are:
Air-conditioning vents, smoke detectors, paintings for decoration, wall sockets, TV sets, bottles and jars on the desk, bathroom hangers and mirrors, etc.
It is strongly recommended to carefully check even of the above mentioned areas.
Outlet is also another but it is relatively easy to identify.
Smoke detector cameras are widely sold over amazon and other marketplaces.
Some of the spy cameras are placed inside the air conditioner vent in an overlooking position which is difficult to detect.
Hidden cameras installed inside the mirror is among one of the most difficult ones to detect by human eyes as it doesn’t have the recognizable black dot like other equipments.
E. Always Read Reviews Before Booking a Room
Always read reviews while booking a hotel. Avoid the ones with reported cases of spy camera installation as this malicious act is usually not limited to just one room.
F. Detect Using RF
Principle: According to the “Hall effect”, electrical devices such as pinhole cameras emit radio frequency when they work.
However, in real application, this method isn’t quite effective because there are often various electrical appliances and cables indoors and in the walls, which will interfere with the RF signal and cause false detection.
If the camera is installed inside the TV, the TV would already transmit RF.
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