How embarrassing: Xiaomi and Motorola show up to high school prom both wearing remote-charging tech

Motorola and Lenovo are experimenting with wireless charging tech that works remotely, casting power to phones and wearables from across the room. Xiaomi's tech – called Mi Air Charge – purportedly offers charging speeds of 5W, and works within a radius of "several meters", which is as vague a metric as any. It consists of two …

[druck]

Waste and saftey

Not only is wireless charging very wasteful, but what about the safety? No matter how good the beam forming, to get 5W charging at several meters away, how much total microwave energy is emitted, and how much are the occupants of the room going to be subjected to?

[Yet Another Anonymous coward]

Re: Waste and saftey

It's not microwaves - it's more like AM radio

[Martin an gof]

Re: Waste and saftey

It can be both.

'Microwaves' implies a particular range of frequencies, 'AM' is a type of modulation. If you mean 'medium wave' (the frequency range used for AM broadcasting) then beamforming at those frequencies requires large aerials spread over a large area.

Horribly inefficient barely begins to describe it, I'd think, also quite likely horribly illegal at the moment, at any frequency.

M.

[Yet Another Anonymous coward]

Re: Waste and saftey

I meant they use frequencies closer to AM radio bands. A magnetic field at a few 100Khz isn't going to deposit very much energy into you compared to a microwave.

On the downside a regular tinfoil hat isn't going to shield you from such long wavelengths.

Back in my days of trying to make super sensitive particle detectors in a world full of badly built CRT flyback transformers radiating like mad, I can suggest that the only effective shielding is something like the magazine armour on a battleship.

[DS999]

Re: Waste and saftey

You sure they use KHz frequencies? Those can't be aimed very well. Higher frequencies can, which makes them much more desireable from a beamforming and efficiency standpoint.

Apple had been working on this for a few years with an acquisition in that field a while back, but apparently gave up a year or two ago - the return of MagSafe seems to be their final surrender on that front. I wonder if these guys figured out something Apple couldn't or if Apple gave it up because of unsolvable problems that will be present in these (assuming one or the other actually reaches the market someday)

[Persona]

Re: Waste and saftey

The wavelength for 100kHz is ~ 3km. A phased array needs to be several wavelengths across to allow accurate beam forming. This sounds a bit bulky for a phone accessory.

[Martin an gof]

Re: Waste and saftey

Indeed. This is what a directional MW transmitter looks like! (Google Maps link). I believe this was 1152kHz?

M.

[werdsmith]

Re: Waste and saftey

Ahhh, memories of childhood road trips and passing the M1 M6 junction and seeing the long since gone Rugby arrays that was one of the triggers that sent me down the tech path.

[Timo]

Re: Waste and saftey

Article mentioned millimeter waves, which puts it into the range of 30-300 GHz. At that frequency it behaves much closer to light and would need to be direct line of sight to operate.

https://en.m.wikipedia.org/wiki/Extremely_high_frequency

[DS999]

Re: Waste and saftey

I think everyone working on this understands that LOS would be required. But that would be fine for what I would like to have it for - if I could have a little tower that would top up my phone I leave sitting on my desk, trickle charge a wireless mouse and airpods that would be great. If I had a watch/fitness band that could be charged too (if the tower was to my left since I would wear a watch on my left wrist if I had one)

Ideally it would keep a laptop charged also, but that's a lot more power especially to keep it charged while in use. But even if it couldn't charge at the rate the battery was depleted it a smaller amount of charge could keep it from running down as quickly during heavy use.

I wouldn't care if something in the way stopped the charging - by selecting the location for the tower properly (mounted in the ceiling above you might be the best solution) it could have LOS to everything you need.

Efficiency isn't a big concern personally, but if you multiply that by a few billion people using it it would really start to add up. If I had solar panels (not an option in my current house due to huge trees shading my roof) in a net zero (at least for electricity) home then I wouldn't feel guilty even if it was only 1% efficient. Though it would not be wrong to be concerned about where the other 99% was going lol

[Anonymous Coward]

Re: Waste and safety and usability

Besides the waste and the safety of the radiation, I can't help but wonder what it's going to do to my wifi and 4g/5g reception. I have 6 foot cords for my phone and tablet chargers so I can charge them during the day while I'm sitting and using them.

[werdsmith]

Re: Waste and safety and usability

Piggy back your wifi on the lower beam.

[The Man Who Fell To Earth]

Re: Waste and saftey

Agreed. In an earlier life at a startup in the 90's, I had to be the RF safety guy. At first blush, kind of hard to see how one could stay under the max permissible RF & microwave exposure levels* while inefficiently transmitting 5W (delivered power) across a room.

*At the time (early 90's), in the USA and UK, permissible RF & microwave exposure levels were a maximum power density of 10mW/cm2 and exposures should not exceed 1mW/cm2 for a continuous period of less than 0.1 hour. In the Former Soviet Union, the limit was 0.01mW/cm2 for one working day, and wearing protective equipment was required for exposures not to exceed 1mW/cm2 for 20 minutes or 0.1mW/cm2 for 2 hours. I don't know if the limits are different today, but I would doubt they have been raised.

[martinusher]

Re: Waste and saftey

Currently people are going crazy about the negative effects of 5G radiation. They're probably not going to like focussed R/F beams being used to send energy to devices in the same environment as they are. The press releases are a big vague about how this works but an article about this a couple of years ago and a company called "Energous" (who seems to hold the IP on this technolgoy) talks about "locating devices using Bluetooth and then sending out tightly focused beams of R/F to the device where a technology called "rectification" (!) turns the received R/F energy into useful power.

As an engineer I think of this technolgoy as clever, ingenious and utterly impractical. Its not that it doesn't work or can't be used but its probably not the best thing to have around people. Cell phone radiation is very low power and very intermittent. This is significantly higher power and continuous. I suppose if it was done right it could do away with the Teasmade.

[Blackjack]

Why?

I can see why people would want fast charging and even why they would want wireless charging.... but what the fudge you need remote charging for in an smartphone?

Yo jusyu know people will just end moving the device as close as possible so it charges faster.

[don't you hate it when you lose your account]

Re: Why?

For those not willing to get off their pampered arse to plug their phone in. Shakes head

[Clunking Fist]

Re: Why?

Aha, that's why you must have a few wireless charging pads dotted around the place: next to armchair, on computer desk, next to bed, etc.

[Avatar of They]

Re: Why?

Yeah at the bad efficiency being talked about it would have to be real close.

Perhaps as close as a short cable length, maybe it will need some kind of matt to rest on as well as it charges?

[Kevin McMurtrie]

It's a cold winter night

Huddle around the mmWave charger for warmth.

I wonder if these chargers occasionally cook electronics when they have metal features coincidentally tuned to the charging field. Certain semiconductors have extremely low avalanche voltages.

[The Man Who Fell To Earth]

Re: It's a cold winter night

Great for those cataracts. Not so good for your vision.

[Anonymous Coward]

What's nice about wired is they're very few things that can go wrong. and a few things that can go wrong can quickly be rectified with your fingernails , or some wire strippers if you carry them around with you,and anything of sufficient insulating properties you have around

Over engineered worships of unnecessary complexity like this are fine for showing off and geewizz points,

But in the real world, wireless just means more fruitless calls to support until you finally get serious and hardwire for dependability.

[Michael Wojcik]

I agree in general, though I'll note that I just had to replace a phone because the tongue snapped off in the micro-USB charging port on the old one, so when I inserted the cable (not having thought to peer into the port first) the pins bent. That's a hard one to repair without a bunch of tools I don't have readily to hand. I've soldered components onto PC boards by hand now and then, but phones are awfully small and my eyes are older.

That still didn't persuade me to get a new phone with wireless charging, though. I can't stomach the inefficiencies, and as you say extra complexity is asking for extra trouble. The new phone has USB-C, which looks like it might be a bit more mechanically durable. And it's a Moto G8 Power, with a great honking 5Wh battery, so I only have to charge it every few days anyway.

Still, I miss barrel connectors. I have a ten-year-old laptop with a barrel-connector charging plug that has never given me any trouble.

[sev.monster]

In my experience barrel connectors do not scale down very well due to their design. How many times have you borked a barrel connector, because I've done it maybe 15 times total—the tiny 5W ones for SBCs. I've broken maybe 4 USB-A and 2 USB-Micro cables in my time, meanwhile, and I've used a hell of a lot more of those. Been using the same C cable on my XA1 every night for many years now (but never charge above 80%!) and I haven't had a lick of trouble; cable still snaps in to place reassuringly and has not had issues charging.

[chuBb.]

Horribly inefficient but could be useful

Useless idea for consumer tech, could have some very useful uses, medical devices for one, especially ones aimed at young children where the lead severely limits the effectiveness given inability to sit still, assistance buttons for the elderly that don't require remembering to plug in.

As for home use unless you live in a minimalist IKEA nightmare pretty sure speed of charge trumps lack of cable or charging coaster.

[Steve Graham]

Nobody's mentioned Nikola Tesla yet?

[_LC_]

A cradle with two contacts

A cradle with two contacts, where you can drop in your SmartPhone to get it charged, is all we need. Instead, we get the choice between this and plugging in a cable for the 1000th time.

[Chris G]

Re: A cradle with two contacts

In other words, a docking device.

That's so old school and not new, innovative, shiny or disruptive, it doesn't matter if that is all that is needed. Marketing wonks have less attention span than a goldfish and think everyone else is the same, they must always have something new to tempt us with.

Still, at least the thought of even more EMF washing through our homes will drive the crazies even crazier.

[John 110]

Re: A cradle with two contacts

What? Like my cordless phones? (Or any cordless phone I've had - ever!)

[The other JJ]

Re: A cradle with two contacts

Or just about every handheld mobile before the late '90s.

[Dan 55]

Re: A cradle with two contacts

This is where I idly wonder how much an old Nokia phone and a car kit cradle would cost on eBay, you know those mid-90s to mid-00s models which had the pop port.

[PerlyKing]

Re: A cradle with two contacts

Like the Sony Xperia charging system? Too useful; discontinued :-(

[Michael Wojcik]

Re: A cradle with two contacts

Next you'll be suggesting that phones should come with swappable batteries you can charge separately from the device itself, you madman.

[Josh 14]

Re: A cradle with two contacts

Or you know, an already common and well distributed standard, something like the Qi charging protocols...

[Anonymous Coward]

Beam me up Scotty.

[Glen 1]

Three Body Problem Trilogy

Reminds me of the Three Body Problem Trilogy

In the later books, set in the future, they have all the flying cars and stuff, and they are powered by induction.

Since fusion had long been mastered and power was no longer scarce - it was more convenient to transmit the power via induction (even with the massive inefficiencies), than it was to carry the extra weight of the charging/generating infrastructure on the craft.

With the power transmission infrastructure in place, *everything* was powered that way.

Interesting times.

[martinusher]

Re: Three Body Problem Trilogy

..and that waste power goes where?

[John 110]

Re: Three Body Problem Trilogy

@martinusher

...into your fillings...

[Persona]

Lets hope that whatever radiation the charging system uses it is not significantly attenuated by going through people otherwise an interesting hack would be to direct the beam at a person you didn't like and slowly cook them.

[Glen 1]

You can already do that with a strong enough light bulb.

[Friendly Neighbourhood Coder Dan]

Perfect

They are the charges I've been dreaming of for years.

I would definitely upgrade my Juicero for a completely wireless model with remote charging! I could take it with me from room to room, no faffing about with the power lead

[Dan 55]

Re: Perfect

... and your house would resemble a microwave?

[dajames]

Re: Perfect

I would definitely upgrade my Juicero ...

So you're the person who bought one? A link might have been helpful for those with short memories!

Upvoted for stealth irony.

[Michael Wojcik]

Re: Perfect

I would've thought "Juicero" would have been a sufficient hint, but apparently you extracted a lot of whoosh there.

Personally, I'm looking forward to using this technology to recharge my AR glasses and electric car.

[Mike 16]

Prior Art?

By any chance are the folks from uBeam involved?

How about the novel solution used by Daystrom's M5 to deal with the pesky red-shirt that tried to unplug it?

https://www.imdb.com/title/tt0708481/

[Pascal Monett]

Dear. God.

So, we have the abomination that is wireless charging, and now they want to have us subject ourselves to a radiation emittor 24/7 on the off-chance that our mobile phone needs its battery topped off.

Please continue to reference that article on how iffy wireless charging is. Someone has to put a stop to this madness, which has just gotten worse.

Is remote charging more inefficient ? I say it bloody well has to be. Wireless charging has you at least going to the effort of placing your blower on a pad (God that must be exhausting), remote wireless means that the charging thingy is emitting energy in a sphere. I'm impressed that anyone should imagine beam-forming capabilities in a sub-€1000 charger, but I personally doubt there's going to be a beam of any sort. That darn thing is just going to blast power in all directions, and everyone and everything will be subject to it.

I wonder how cats and dogs are going to react to that. I wonder how fish in aquarium are going to appreciate their water heating up.

Please stop the madness. Ban wireless charging now.

[PerlyKing]

Re: Dear. God.

Er, Pascal, while I agree about inefficiencies you seem to have missed the bits in the article about the Xiaomi phone having an active beacon and the transmitter steering the beam, and for the Motorola system "Any obstacle placed between the charger and the phone immediately halts charging".

Otherwise, rant on!

[dajames]

Re: Dear. God.

...for the Motorola system "Any obstacle placed between the charger and the phone immediately halts charging".

Hmm ... I read that as "if you interrupt the beam the phone won't see it" rather than as "if you interrupt the beam the charger will stop beaming" ... but you may be right?

[Dominic Sweetman]

Poppadom

5W is not much power, so won't cook anything. 30-300GHz waves (see wikipedia) won't travel long distances through air, so are not likely to be used for regulated communication. They'll have no biological effect except for heating. Presumably the transmitter only turns up the power when it finds a friendly chargee, so walk through the beam and it turns off. Small-device chargers are never going to represent more than a small fraction of anyone's electricity use, so efficiency isn't critical.

Too clever by half? Perhaps. And since all companies always want to make incompatible chargers, your ceiling will be festooned with battling chargers...

[Dan SVN]

Big players now want a piece of long distance wireless charging!

Smaller companies like WiTricity, Energous, GuRu, Ossia, Wi-Charge, ... have been trying to bring a true wireless charger to the market for years. Now that big cell phone companies are putting their effort behind it, I hope to see this soon in phones.

It is interesting that Xiaomi is using mmWave tech similar to what GuRu is using. I wonder if it can piggy back over 5G hardware to deliver both data and power at the same time.

[dc_m]

I've got a Xiaomi Poco, it's a great piece of kit and it's not a flagship phone by any means. It does however need a full 3 amps to charge it properly, I know this because of experimenting with a 2.4a magnetic cable. I can't help thinking that's rather a lot of current to be whistling through the air.

[mtp]

It will never happen

Let EEVBlog tell you

https://www.youtube.com/watch?v=X6JDOXjvKAI