Researchers invent 'anti-Wi-Fi' paint that blocks wireless signals

University of Tokyo researchers have developed special paint that can block wireless signals.

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University of Tokyo researchers have developed special paint that can block wireless signals.

By mixing aluminum-iron oxide particles into paint, the researchers have invented paint that blocks radio frequency in higher spectra where Wi-Fi and other higher-bandwidth communications occur.

Though most Wi-Fi technologies operate at 2.4GHz and 5GHz, the special paint can block frequencies all the way up to 100GHz, the researchers said.

A 200GHz-blocking paint is under development.

Here's how it works: the metal particles within the paint resonate at the same frequency as Wi-Fi and other radio waves, so signals can't pass through the thin layer of pigment. Voilà: a secure wall that stops signals from entering the house and yours from breaching walls coated with the special paint.

The use for such a novel product is already present. Movie theaters have been interested for quite some time in finding a legal way to silence cell phones during screenings. (Electronic jammers that actively block wireless signals are illegal.)

But that's not all. One of the researchers, project lead Shin-ichi Ohkoshi, spoke to the BBC:

"In a medical setting, you could transmit large volumes of data from a medical device, such as an endoscope, to a computer. You could block phone signals from outside and stop people's phones ringing during the movie. By painting a solution containing our magnetic particles on the walls, you would quickly, and effectively, shield the room from stray electromagnetic radiation from outside."

The debate would then be how dangerous such a system would be during a disaster in which emergency communication would be necessary.

Security's also a concern, too. After all, what do you do when you have to open the door?

UPDATE: SmartPlanet's Dana Blankenhorn makes the case for what he thinks is the real value in anti-Wi-Fi paint .

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