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Linux-based gadget charges mobiles wirelessly at up to 15 feet

Jan 9, 2015 — by Eric Brown 2,565 views

Energous demoed a Linux-based “WattUp” device that uses WiFi-like beam forming technology to wirelessly charge compatible mobile devices at up to 15 feet.

Energous received a lot attention for its WattUp long-distance wireless charging hub at this week’s CES show in Las Vegas. Now, a rep from the startup has confirmed to LinuxGizmos our suspicions that the device runs an embedded Linux OS.

Typical living room with wall-mounted WattUp wireless charging hub
(click image to enlarge)

The device’s Linux foundation is not surprising when you consider that the WattUp acts more like a WiFi router than a traditional wireless charging pad. WattUp uses the same 5.7-5.8GHz frequency bands as WiFi, focused with patent-and trademark-pending beam-forming technology, to charge targets up to 15 feet way.

Wall-mounted (left) and tabletop (middle) Wattup charging hubs with displays, and a simple non-display hub (right)
(click images to enlarge)

Using an always-open 2.4GHz Bluetooth Low Energy (BLE) communication channel, the WattUp charging hub tracks the “location, orientation, battery condition, and other pertinent information” of up to 12 devices. You can charge more than one device at once, even when the devices are in motion or being used. The hub’s software determines “which devices receive power, when, and in what priority,” says Energous.

Wattup Android app
(click to enlarge)
Priority designations follow customizable rules such as giving higher priority to cell phones during peak hours and lower priority to devices such as TV remotes and cameras. Mobile apps, which can be run from remote locations, let you tweak the priorities and set the charging schedule.

To make the magic work, however, the devices must have BLE, as well as integrated WattUp receiver chips. The chips convert WattUp’s focused radio waves into DC power using a “metamaterial array” — specialized MIMO antennas — where ASICs convert the RF energy into DC. If there are no authorized devices within range, the WattUp transmitter goes idle to save power.

Tabletop and wall-mounted WattUp chargers wirelessly transmitting power to mobile devices
(click images to enlarge)

Any WattUp compliant device that runs on 10 Watts or below is supported. These are said to include smartphones, tablets, e-readers, smartwatches, fitness trackers, remotes, home automation sensors and lights, and battery powered toys.


Cool stuff — but will it turn our brains to jelly? Energous assures us that since WattUp uses the same frequencies as WiFi and coreless phones, our gray matter will be no more discombobulated than usual. The RF energy is split into numerous micro-waveforms so “the energy density at any one point in the room is extremely low,” says Energous. Cellular frequencies are much more penetrative, the company adds.

Some press reports have tossed around charging distance numbers as high as 20 to 25 feet, but the website offers only the following claims, which top out at 15 feet:

  • 4W delivered simultaneously to 4x devices, 0-5 feet — charging at same rate as power outlet
  • 2W delivered simultaneously to 4x devices, 5-10 feet — charging at same rate as USB port
  • 1W delivered simultaneously to 4x devices, 10-15 feet — charging at ~1-2% per minute
  • Average of 2W to 4x devices simultaneously within the charging envelope
  • Maximum of 12x devices at 0.25 Watts

Energous, which was named a 2015 CES Innovation Awards Honoree in the Smart Home, Portable Power and Embedded Technologies categories, will be targeting the WattUp at OEM customers. The company announced a deal with electronics OEM giant Foxconn, which will be evaluating the technology for inclusion in a variety of its products.

OEMs can license the WattUp proprietary chip technology and design libraries, scalable transmitter and receiver reference designs, and software stacks ranging from device firmware to cloud-based enterprise management tools. Other offerings are said to include high volume technology transfer readiness documentation, custom design and applications engineering support, as well as “patent, knowhow and comprehensive intellectual property coverage.”

It will take time for mobile devices to integrate WattUp receivers, and that assumes the technology is proven and cost effective in the first place. In the meantime, Energous says that WattUp battery packs that include the receiver will begin shipping by the end of the year at the same price as normal battery packs, according to a hands-on report from The Verge. Apparently, manufacturers have told Energous they can shrink the batteries enough to make room to add the receivers at about the same cost.

The WattUp transmitter devices, meanwhile, will cost around $300, says The Verge. The demo models in the faux home set in Vegas were the “size of a few laptops stacked together,” but Energous will shrink that by a factor of six by the time they reach market, says the story.

According to an Engadget report, the transmitters can be built into household appliances, TVs, speakers, and standalone “energy routers.” The devices will support “closed network” environments such as public spaces where devices must first be registered for charging, as well as open networks such as a home, says the story. The technology is also said to support automatic handovers from transmitter to transmitter for seamless charging.

In addition to the Foxconn deal, Energous has signed up South Korea’s SK Telesys, and a few smaller companies such as Haier, says Engadget. It is also working with Innovation First International, which makes the Hexbug line of miniature robot toys. The first commercial rollout of transmitters and devices with pre-integrated receivers could occur as early as 2016, Energous told the publication.

Energous also announced it has joined the Power Matters Alliance. The company will chair a newly formed Uncoupled Power Working Group (UPG) to develop common specifications for long-distance wireless charging. The UPG will be able to test the WattUp partners’ devices and provide interoperability certification, says Energous.

“We believe we are the only CES exhibitor to be demonstrating true wire-free charging technology that lets users roam while their devices charge,” stated Stephen R. Rizzone, CEO of Energous Corporation.

Further information

The WattUp wireless charging technology is available now to OEMs for licensing in various forms, and could reach market as early as 2016. More information may be found at the Energous website

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