This Transmitter Will Charge Your Gadgets Through The Air

Usually, when tech companies speak rhapsodically about “wireless power,” what they mean is, “you can recharge your phone by setting it down on a mat.”

Well, OK. It’s slightly easier to put your phone down on a mat than to plug in its power cord.
Samsung built charging-mat receiver technology into its Galaxy S4 , S5 and S6 phones.

Example is Samsung Galaxy 6 Edge

But that’s not really wireless charging. It’s not charging through the air, like a WiFi signal. You can’t keep using the phone while it’s charging.

No wonder the wireless-mat thing hasn’t really caught on.....
The next wave, though, will probably get your attention.

Meet RF charging

At labs all over the world, engineers are getting true, distance charging technologies ready. That’s just what it sounds like: Thanks to a special transmitter, your phone, tablet, smartwatch, hearing aid, and fitness band will be charging all the time, as you go about your day. You won’t take them off. You won’t plug them in. And you’ll never worry about making it through the day on a charge.

The transmitter: a shiny black plastic box that looked something like an oversized WiFi router.

A product’s battery life, in fact, will become irrelevant.

So how close are we to this fantasy? Very, according to Steve Rizzone. He’s the CEO of a 50-person company called Energous, whose distance-charging technology (with the unfortunate name WattUp) is, he says, by far the closest to being ready for market. He came by Yahoo’s New York office to give me a demonstration.

Using a tablet as a remote control, he could turn on the transmitter; at that point, the phone’s “charging” indicator came on, right there in my hand—not plugged into anything. The phone was, in fact, getting an electric charge through the air.

Rizzone also had an electric votive candle on hand; its low power requirements were meant to represent a smartwatch or fitness band. Once again, he could tap a software switch on his tablet to make the candle light up, indicating that it was getting power.

Charging Through The Air.

The Frequently Asked Questions

Q: Is this going to fry my guts?

A: No. The transmitter is sending out an RF (radio-frequency) signal—the same kind of signal transmitted by WiFi or cellphones. Not only is the signal even weaker than your phone’s, but it’s reflective; it bounces off skin instead of going through it.

(To underscore the inability of these waves to penetrate the skin, Rizzone told me a story about a pacemaker manufacturer who contacted him. The manufacturer was all excited about WattUp. Imagine if we could recharge people’s pacemakers without requiring surgery to change the battery!
But there ya go. That won’t happen, because RF waves bounce off the body.)

Q: How does it work?

A: The transmitter contains an array of small RF antennas. They send out “23 dBm across a 120-degree directional span, creating a 3D pocket of energy using the 5.8GHz unlicensed ISM RF spectrum.”

Translated from Engineerspeak, that means a focused pocket of power will be collected by any receiver-equipped gadget that happens to be within a 120-degree arc from the transmitter.

The hard part is not wireless charging, Rizonne says; it’s focusing the array of antennas on each gadget. In WattUp’s implementation, your gadget’s Bluetooth circuitry provides a focusing target for the RF beams that converge from floor, ceiling, wall, and furniture reflections.

Q: Can it charge more than one thing at once?

A: Yes—up to 12 devices simultaneously.

Q: What’s the range?

A: The strength of the charging drops off rapidly with distance; at the moment, 15 feet is the maximum range of the transmitter.

At 5 feet, your gadget (actually, four of them at once) can receive a maximum of 4 watts. At 10 feet, it gets 2 watts; at 15 feet, 1 watt.

Q: Is the transmitter sucking power all the time?

A: No. When there aren’t any WattUp receivers in range, Rizzone says that the transmitter goes to sleep.

Q: What’s the deal with the tablet he’s using?

A: The WattUp system is designed to be configurable. You can specify which gadgets get priority when they’re in range, using either the phone/tablet app or a Web portal. You can also set up a schedule, so that cellphones get priority when you’re home, but your remote controls and wireless mouse get charged while you’re away.

Q: How much?

A: The transmitter will probably cost around $300; the necessary phone case to receive the signal will be in the $75 to $125 range, Rizzone says.

Q: When?

A: Steve told me that they expect these products to be available at the end of 2016 or early 2017. That’s only a year and a half from now!

Now the problem is will Mobile manufacturer built RF Charging ..
Samsung built charging-mat receiver technology into its Galaxy S4 , S5 and S6 phones.
Example is Samsung Galaxy 6 Edge