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Scientists have developed a wireless charging chamber that can power any laptop, tablet or mobile phone through the air without the need for plugs or cables.
The team at the University of Tokyo said the new technique involves generating magnetic fields over longer distances without creating electric fields that could be harmful to anyone or animals in the room.
The system, which has been tested in a room but is still in its infancy, can deliver up to 50 watts of power without exceeding current guidelines for human exposure to magnetic fields, the study authors explained.
It can be used to charge any device with a coil inside, similar to the system used by current wireless charging pads — but without a charging pad.
In addition to removing bundles of charging cables from desks, it could allow more devices to be fully automated without the need for ports, plugs or cables, the team said.
The team said that the current system includes a magnetic pole in the center of the room to allow the magnetic field to “reach every corner”, but works without it, a compromise being a “dead spot” where wireless charging is not possible.
The researchers did not disclose how much the technology would cost because it is still in the early stages of development and “years away” from being available to the public.
However, when it is possible to retrofit an existing building or integrate into a completely new building, with or without a central conducting pole.
The technology will allow any electronic device – such as a phone, fan or even a lamp – to be charged without the need for cables, and as seen in this room created by the University of Tokyo, it proves it works.Unseen is the central pole, which acts to increase the extent of the magnetic field
The system includes a post in the center of the room to “fill in gaps not covered by wall capacitors,” but the authors say it would still work without the post, as shown, but would result in a dead spot where charging wouldn’t work
Lumped capacitors, designed to separate the thermal system, are placed in the wall cavity of each wall around the room.
This reduces the risk to humans and animals in space, as electric fields can heat biological meat.
A central conductive electrode is installed in the room to generate a circular magnetic field.
Since the magnetic field is circular by default, it can fill any gaps in the room not covered by wall capacitors.
Devices such as cell phones and laptops have coils inside that can be charged using magnetic fields.
The system can provide 50 watts of power without any risk to people or animals in the room.
Other uses include smaller versions of power tools in toolboxes, or larger versions that can allow entire plants to operate without cables.
“This really enhances the power of the ubiquitous computing world — you can put your computer anywhere without worrying about charging or plugging in,” said study co-author Alanson Sample from the University of Michigan.
There are also clinical applications, according to Sample, who said heart implants currently require a wire from a pump to pass through the body and into a socket.
“This could eliminate this condition,” the authors said, adding that it would reduce the risk of infection by eliminating wires entirely, “reducing the risk of infection and improving the patient’s quality of life.”
Wireless charging has proven controversial, with a recent study finding that the type of magnets and coils used in some Apple products could shut down pacemakers and similar devices.
“Our studies targeting static cavity resonances do not use permanent magnets and therefore do not pose the same health and safety concerns,” he said.
“Instead, we use low-frequency oscillating magnetic fields to transmit electricity wirelessly, and the shape and structure of the cavity resonators allow us to control and direct these fields.
“We are encouraged that our initial safety analysis showed that useful power can be transferred safely and efficiently. We will continue to explore and develop this technology to meet or exceed all regulatory safety standards.
To demonstrate the new system, they installed a unique wireless charging infrastructure in a purpose-built 10-foot-by-10-foot aluminum “test chamber.”
They then use it to power lights, fans and cell phones, drawing electricity from anywhere in the room, no matter where furniture or people are placed.
The researchers say the system is a significant improvement over previous attempts at wireless charging, which used potentially harmful microwave radiation or required placing the device on a dedicated charging pad.
Instead, it uses conductive surfaces and electrodes on the walls of the room to generate a magnetic field that devices can tap into when they need power.
Devices utilize magnetic fields through coils, which can be integrated into electronic devices such as cell phones.
The researchers say the system can be easily scaled to larger structures, such as factories or warehouses, while still meeting existing electromagnetic field exposure safety guidelines set by the U.S. Federal Communications Commission (FCC).
“Something like this is easiest to implement in new buildings, but I think retrofits are also possible,” said Takuya Sasatani, a researcher at the University of Tokyo and the study’s corresponding author.
“For example, some commercial buildings already have metal support rods and it should be possible to spray a conductive surface onto the walls, which could be similar to how textured ceilings are made.”
The study authors explain that the system can deliver up to 50 watts of power without exceeding FCC guidelines for human exposure to magnetic fields
The study authors explain that the system can deliver up to 50 watts of power without exceeding FCC guidelines for human exposure to magnetic fields
The magnetic field describes how the magnetic force is distributed in the area around a magnetic object.
It includes the effect of magnetism on mobile charges, currents and magnetic materials.
Earth produces its own magnetic field, which helps protect the surface from harmful solar radiation.
The key to making the system work, Sample says, is to create a resonant structure that can deliver a room-sized magnetic field while confining harmful electric fields that can heat biological tissue.
The team’s solution uses a device called a lumped capacitor, which fits a lumped capacitance model — where the thermal system is reduced to discrete lumps.
Temperature differences within each block are negligible and are already widely used in building climate control systems.
Capacitors placed in wall cavities create a magnetic field that resonates in the room while trapping the electric field inside the capacitor itself.
This overcomes the limitations of previous wireless power systems, which were limited to delivering large amounts of power over tiny distances of a few millimeters, or very small amounts over long distances, which could be harmful to humans.
The team also had to devise a way to ensure their magnetic field reached every corner of the room, eliminating any “dead spots” that might not charge.
Magnetic fields tend to propagate in circular patterns, creating dead spots in square rooms and difficult to precisely align with the coils in the device.
“Drawing energy in the air with a coil is a lot like catching butterflies with a net,” Sample said, adding that the trick is “to get as many butterflies as possible to spin around the room in as many directions as possible.”
By having multiple butterflies, or in this case, multiple magnetic fields interacting, no matter where the web is, or which way it’s pointing – you’ll hit the target.
One circles the central pole of the room, while the other swirls in the corners, weaving between adjacent walls.
It can be used to charge any device with a coil inside, similar to the system used by current wireless charging pads – but without a charging pad
The researchers did not say how much the technology might cost, as it is still in the early stages of development, but it “will take years” and could be retrofitted to existing buildings or integrated into entirely new buildings when available middle
According to Sample, this approach eliminates dead spots, allowing devices to draw power from anywhere in space.