Disney develops wireless electricity
Soon you might be able to charge your phone just by entering a room, and it's not a Mickey Mouse idea. Cathal O'Connell reports.
Thanks to the Walt Disney
Company, wall plugs might become a thing of the past. Scientists at Disney Research
have found a highly efficient way to deliver power to devices wirelessly across
a room, using magnetic fields.
More than a century ago the great inventor Nikola Tesla unveiled a plan to provide free electricity to the world: he proposed setting up a wave of electricity bouncing constantly between the Earth and the upper atmosphere. All electrical devices would be tuned to the frequency of this wave and receive energy from it, creating a wirelessly powered world.
“Well that idea didn’t really work out,” says Alanson Sample, who leads the Wireless Systems group at Disney Research, “but it gave us some inspiration for ways to set up wireless power in large spaces.
“What we really want is a three dimensional charging experience where you walk in into your living room or office, and your cell phone is charged simply by walking in.”
One problem with Tesla’s plan was it used very high voltage electric fields, which are potentially dangerous. Instead, Sample and his team use oscillating magnetic fields, which harmlessly pass through human bodes – and anything else.
Devices such as phones or computers, anywhere in the space, can tap in to wireless power using internal circuitry that resonates at the same frequency as the magnetic field—a bit like how a tuning fork can resonate if you hit the right note on a piano.
After working their idea out on paper, Sample and his team tested it by building a special room and powering various devices inside. A copper pipe was erected in the middle of it – a little like a pole-dancing set-up – while the walls, ceiling and floor were lined with aluminium panels.
Currents ran up and down the pole 1.3 million times per second, generating an oscillating magnetic field at that frequency.
The field can deliver up to 1.9 kilowatts of power inside the room, “which is equivalent to charging 320 USB devices,” the authors write in PLoS One. In a demonstration, Sample’s team operated lamps, a fan, a toy car, a phone, a fan and some LEDs simultaneously.
Cleverly, the wireless system doesn’t generate a strong field unless a device is tapping in to it—so energy is not wasted when the room is empty. Lights off means power off.
Just don’t bring your device too close to the pole: that could damage it, or wipe its memory. The team propose adding a decorative wall or barrier to prevent this.
According to Sample – who worked previously on wireless systems for cardiac implants – the technology could be scaled scaled down to make a charging box for a toddler’s toys, or scaled up to the size of a warehouse.
The current design, however, results in a significant problem. With the walls, ceiling and floor all made from aluminium panels, outside signals are blocked. Your phone might be charging in your pocket, but it won’t receive any calls. As the system improves, though, there may be scope to reduce the amount of cladding and let some data through.