Wireless signal shaper can put your Wi-Fi into the nooks and crannies of your home – and keep it from spilling out into the rest of the world
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It should be known as the Wi-Fi dance, practiced by frustrated laptop, tablet and smartphone users wafting their devices in the air in the hope of picking up an elusive wireless signal in their home. Meanwhile, anyone passing by on the street outside can easily pick up the network.
Now there may be a quick and relatively easy solution to these Wi-Fi woes.
Researchers at Dartmouth College in Hanover, New Hampshire, have developed customised reflectors that can precisely control the shape of the Wi-Fi signal from a router.
While repeaters merely boost an existing signal in hard to reach parts of the home, the new tech also allows it to be reduced it in others, such as near windows, to help prevent anyone outside snooping on your network. This could offer some peace of mind to people worried about their wireless connection being exploited by outside hackers engaged in so-called Wi-Fi sniffing and wardriving.
“We can weaken the signals outside so that it’ll be hard for others to get connected to your access point,” says Xia Zhou, a computer scientist at Dartmouth who led the research.
Problems with her own Wi-Fi led Zhou to online do-it-yourself reflectors fashioned from cut up aluminium drinks cans that can be wrapped around the router’s antenna. While these have been shown anecdotally to boost Wi-Fi signals, Zhou and her colleagues felt they could do better.
They designed an algorithm that can calculate the ideal shape of a reflector needed to change the Wi-Fi signal coverage to a user’s specifications. The user needs to feed the system with a rough 3D model of their home, including the position of walls, doors and windows – something that can be generated using simple software used for home interior design – along with the location of the router.
They can then specify where they want to boost and reduce the wireless coverage. For example, they might want the Wi-Fi in their kitchen to be increased, but to reduce the signal bleeding out the front of their home onto the road.
The algorithm models the signal distribution in the home and then computes the optimal reflector shape needed to change it. The resulting reflector can then be 3D printed – Zhou’s prototypes were printed in plastic before being wrapped in kitchen foil so they could reflect radio waves. “Since we compute the reflector shape by taking into account the environment, such as where the walls are, we can bounce the signals in a way that mitigates the impact of building insulations, partitions, and interior layout,” she says.
As a result, the reflectors were able to boost the strength of a Wi-Fi signal by up to 55 per cent in areas where signal was desired – and reduce it by up to 63 per cent where it wasn’t.
The team are now trying to develop a user-friendly interface to make it easier for people to upload models of their home and shape their Wi-Fi signal. Users could then either print it themselves or upload the reflector specifications to online 3D printing services. Each of Zhou’s prototypes took around 23 minutes to print and cost $35 (£26).
There could be one hitch – Andrew Nix, head of the communication systems and networks research group at the University of Bristol, warns they might not work on the most modern routers, some of which can have three or four antennas working in an array. “I’d be surprised if accurate radio frequency shaping could be achieved on modern units,” Nix adds.
However, the reflectors could mitigate Wifi’s security problem – as long as the threat you’re worried about is low-tech. “They might not offer much protection from sophisticated equipment such as high-gain antennas.”
And don’t let this tempt you into forgoing password protection. “The only way to secure a WiFi connection with any reliability is to encrypt it,” says Alan Woodward, a computer security expert at the University of Surrey.