EEVblog Electronics Community Forum

EEVblog => EEVblog Specific => Topic started by: Barny on June 06, 2018, 05:13:26 pm

Title: EEVblog #1092 - Wi-Charge IR Wireless Charging - Fact or Fiction?
Post by: Barny on June 06, 2018, 05:13:26 pm
http://www.youtube.com/watch?v=2bXjn3wwM8o (http://www.youtube.com/watch?v=2bXjn3wwM8o)

Running the numbers on the W-Charge Infrared laser wireless charging system, does it work?, is it practical?, what is the efficiency?, how much power can it deliver?, is it dangerous?
And the laser power is HOW MUCH?!

CORRECTION: The laser output power was stated incorrectly, it was assuming the input power to the laser when it should have been the optical output power. The correct number for a 45% solar cell and zero other losses is 11.1W laser power, not 18W. Still the same class of laser and just as dangerous.

In response to the Linus Tech Tips demonstration.
Also some talk on the Energous RF Wireless energy boondoggle.
Title: Re: EEVblog #1092 - Wi-Charge IR Wireless Charging - Fact or Fiction?
Post by: Barny on June 06, 2018, 05:18:46 pm
I hope this charge-system gets available for a good price here in Europe.
It starts to get really hard to get other laser then simple laser pointer as a private person thanks to some idiots which decides to point them to landing / starting planes.

The lasers and laser driver in the charger would be nice to cut & engrave wood and perhaps thin sheets of steel.
Title: Re: EEVblog #1092 - Wi-Charge IR Wireless Charging - Fact or Fiction?
Post by: janekm on June 06, 2018, 06:09:38 pm
I hope this charge-system gets available for a good price here in Europe.
It starts to get really hard to get other laser then simple laser pointer as a private person thanks to some idiots which decides to point them to landing / starting planes.

The lasers and laser driver in the charger would be nice to cut & engrave wood and perhaps thin sheets of steel.

All that's needed to transform this gadget into a whole-room engraver is a firmware modification  :-DD
Title: Re: EEVblog #1092 - Wi-Charge IR Wireless Charging - Fact or Fiction?
Post by: Barny on June 06, 2018, 06:20:29 pm
I don't think so.
It would extreme hard to focus the beam longer then a few mm.

But if they switch to UV-Laser, it could be used for mask less exposure of PCB's
Title: Re: EEVblog #1092 - Wi-Charge IR Wireless Charging - Fact or Fiction?
Post by: G7PSK on June 06, 2018, 06:30:37 pm
I am waiting for BMW to upgrade this for there car charging system, just think power on the go while driving down the motor way. All delivered via a weapons grade laser :-DD or  :scared:
Title: Re: EEVblog #1092 - Wi-Charge IR Wireless Charging - Fact or Fiction?
Post by: fls on June 06, 2018, 07:56:26 pm
Maybe stupid question, but does the unit contains one '20W' power diode or maybe several smaller ones?
Marketing talk still holds the '5W delivered power' if you have 5 devices charged by 5 diodes (or maybe even 10 diodes?)
It does not mention that the 5W is per device by 1 diode.
Or am I missing something?
Title: Re: EEVblog #1092 - Wi-Charge IR Wireless Charging - Fact or Fiction?
Post by: Psi on June 06, 2018, 08:08:54 pm
Unlike with visible laser diodes, extremely high power IR laser diodes are relatively affordable.
$300 can get you a 10W solid state IR laser diode and ive seen well over 50W available.

They are super dangerous though, you get no warnings or 2nd chances, one reflection and you are blind.. for the rest of your life.

https://www.aliexpress.com/item/Industrial-Design-10W-10000mw-808nm-laser-diode-module-Brass-18mm-C-mount-IR-laser/32868308008.html (https://www.aliexpress.com/item/Industrial-Design-10W-10000mw-808nm-laser-diode-module-Brass-18mm-C-mount-IR-laser/32868308008.html)

https://www.alibaba.com/product-detail/fiber-laser-50w-100w-high-power_60490362832.html (https://www.alibaba.com/product-detail/fiber-laser-50w-100w-high-power_60490362832.html)

https://www.aliexpress.com/item/100W-oflaser-machines-Diode-Side-Pump-laser-module-for-sale/32859195813.html (https://www.aliexpress.com/item/100W-oflaser-machines-Diode-Side-Pump-laser-module-for-sale/32859195813.html)
Title: Re: EEVblog #1092 - Wi-Charge IR Wireless Charging - Fact or Fiction?
Post by: GeorgeOfTheJungle on June 06, 2018, 08:18:09 pm
Direct sunlight in the best case delivers 1kW/m2 that's 0.1W per square centimeter IIANM. This thingy say 5W into what, 5 square centimeters or so?  That's 1W/cm2 or about ten times as much? Or is that 5W figure after the receiver conversion losses? If so it's perhaps not tens but hundreds of times more powerful than the sun /cm2 !


Title: Re: EEVblog #1092 - Wi-Charge IR Wireless Charging - Fact or Fiction?
Post by: Barny on June 06, 2018, 09:13:28 pm
Unlike with visible laser diodes, extremely high power IR laser diodes are relatively affordable.
$300 can get you a 10W solid state IR laser diode and ive seen well over 50W available.

They are super dangerous though, you get no warnings or 2nd chances, one reflection and you are blind.. for the rest of your life.

https://www.aliexpress.com/item/Industrial-Design-10W-10000mw-808nm-laser-diode-module-Brass-18mm-C-mount-IR-laser/32868308008.html (https://www.aliexpress.com/item/Industrial-Design-10W-10000mw-808nm-laser-diode-module-Brass-18mm-C-mount-IR-laser/32868308008.html)

https://www.alibaba.com/product-detail/fiber-laser-50w-100w-high-power_60490362832.html (https://www.alibaba.com/product-detail/fiber-laser-50w-100w-high-power_60490362832.html)

https://www.aliexpress.com/item/100W-oflaser-machines-Diode-Side-Pump-laser-module-for-sale/32859195813.html (https://www.aliexpress.com/item/100W-oflaser-machines-Diode-Side-Pump-laser-module-for-sale/32859195813.html)

The problem isn't the price.
The problem is to get them through the import customs.
The block nearly all laser and periodically even LED's which are coming from china.
(Specially here in Austria & Germany.)
Till now England was a way to get parts which otherwise get blocked at customs.
But they decided to don't play with us anymore.
Title: Re: EEVblog #1092 - Wi-Charge IR Wireless Charging - Fact or Fiction?
Post by: janekm on June 06, 2018, 09:20:42 pm
Maybe stupid question, but does the unit contains one '20W' power diode or maybe several smaller ones?
Marketing talk still holds the '5W delivered power' if you have 5 devices charged by 5 diodes (or maybe even 10 diodes?)
It does not mention that the 5W is per device by 1 diode.
Or am I missing something?

I did a little skimming of the patents, which are very interesting. According to the patents, is not using a regular laser diode at all but rather a "freespace" lasing system, that is the laser cavity is formed between the transmitter and the receiver (both of which have retroreflectors).
Remembering that "laser" stands for "light amplification by stimulated emission of radiation", that is in this system, light emitted from the transmitter is reflected by the receiver, then reflected & amplified by the transmitter, repeatedly.
This is a very smart idea since it means that anything interrupting the beam stops the lasing directly. Additionally they can use it with some adaptive optics to focus / track the receiver.

Theoretically multiple transmitters could be employed, afaict, since retroreflection would allow each to operate independently (though I wonder about interference?).

The biggest issue of course is if some proportion of the light is scattered or reflected away from the intended optical path.

Like Dave pointed out it all seems a little overkill for charging mobile phones, but there are likely real applications in other fields (sensor networks? micro-satellites?).
Title: Re: EEVblog #1092 - Wi-Charge IR Wireless Charging - Fact or Fiction?
Post by: Psi on June 06, 2018, 09:56:41 pm
Unlike with visible laser diodes, extremely high power IR laser diodes are relatively affordable.
$300 can get you a 10W solid state IR laser diode and ive seen well over 50W available.

They are super dangerous though, you get no warnings or 2nd chances, one reflection and you are blind.. for the rest of your life.

The problem isn't the price.
The problem is to get them through the import customs.
The block nearly all laser and periodically even LED's which are coming from china.
(Specially here in Austria & Germany.)

They block laser pointers, not products that contain lasers.
Otherwise you wouldn't be able to buy any DVD  / Blueray writers which contain 400mW lasers. Or superfast laser printers with high power diodes.
Title: Re: EEVblog #1092 - Wi-Charge IR Wireless Charging - Fact or Fiction?
Post by: Barny on June 06, 2018, 10:40:04 pm
Yes.
But why should I buy a complete laser cutter / engraver when I only need the laser unit for my mill ;)

Ans good luck, getting a complete laser cutter with all its paper work as a private person through imort customs.
A button cell is enough to refuse import.
(µCurrent fom Dave get hit from this stupide rule too.)


@janekm :
Isn't a exact matching length between the mirrors needed for the laser to work?
Title: Re: EEVblog #1092 - Wi-Charge IR Wireless Charging - Fact or Fiction?
Post by: apis on June 06, 2018, 11:14:01 pm
Even if they can make this safe and usable, it won't be cheap enough to become mainstream.

I can't even think of a niche application for it but maybe there is one.

Nice gimmick though.
Title: Re: EEVblog #1092 - Wi-Charge IR Wireless Charging - Fact or Fiction?
Post by: maxwell3e10 on June 06, 2018, 11:22:45 pm
I did a little skimming of the patents, which are very interesting. According to the patents, is not using a regular laser diode at all but rather a "freespace" lasing system, that is the laser cavity is formed between the transmitter and the receiver (both of which have retroreflectors).

This is hard to believe, both because the receiver looks like a simple solar cell and because it would be extremely difficult to maintain alignment of the laser cavity, especially on the moving train demo.

If I were to built a system like that, I would have a low-power flashing IR photodiode, like they use in remote controls, installed in the receiver. The base unit detects this light and uses it both to align the IR laser and as a safety feature. If the IR modulated signal gets blocked, the laser is immediately shut down. This could be done in less than 1 microsecond and so would prevent somewhat the laser getting scattered when something shiny blocks its path.
Title: Re: EEVblog #1092 - Wi-Charge IR Wireless Charging - Fact or Fiction?
Post by: StillTrying on June 07, 2018, 01:26:07 am
This is hard to believe, both because the receiver looks like a simple solar cell and because it would be extremely difficult to maintain alignment of the laser cavity, especially on the moving train demo.

My previous reply to that part was quite simple!
http://www.eevblog.com/forum/chat/infrared-laser-wireless-charging/msg1292229/#msg1292229 (http://www.eevblog.com/forum/chat/infrared-laser-wireless-charging/msg1292229/#msg1292229)

Quote
If I were to built a system like that, I would have a low-power flashing IR photodiode, like they use in remote controls, installed in the receiver. The base unit detects this light and uses it both to align the IR laser

You could be right! The IR could be coded so that you don't get burnt fingers every time you change TV channels.

Good #1092 video, problem is there's now 6 separate threads on this thing.
Title: Re: EEVblog #1092 - Wi-Charge IR Wireless Charging - Fact or Fiction?
Post by: madires on June 07, 2018, 01:34:18 am
I'd assume that "total power delivered" means the total power delivered across the complete lit area. For safety reasons they have to widen the beam anyway. Laser class 1 and 1M are fine for consumer stuff, but any higher class would involve a lot of safety regulations.  Still, as nearer you get to the laser source as narrow the beam will become. With tracking the receiver to send a narrow beam for maximum power transfer they would exceed Class 1(M) anyway. I have strong doubts that they may sell the Wi-Charge to consumers, and also about the efficiency. If my assumption about the delivered power is right we would be talking about <0.1%.
Title: Re: EEVblog #1092 - Wi-Charge IR Wireless Charging - Fact or Fiction?
Post by: grythumn on June 07, 2018, 01:36:45 am
If they can get the power up a bit higher than 5W, it might be useful for long endurance personal mini drone cameras. Run it off a small ultracap, and make them tiny. Right now some of the nano drones run around the 10-30W range.

-Bob
Title: Re: EEVblog #1092 - Wi-Charge IR Wireless Charging - Fact or Fiction?
Post by: bitwelder on June 07, 2018, 05:33:18 am
All that's needed to transform this gadget into a whole-room engraver is a firmware modification  :-DD
Because why not, I'm pretty sure soon or later this gadget will get its own internet connection, there will be a good chance to have a remotely hacked device totally out of control (and because it's IR, nobody would notice it)
Title: Re: EEVblog #1092 - Wi-Charge IR Wireless Charging - Fact or Fiction?
Post by: Barny on June 07, 2018, 06:10:25 am
This Charger would be the ultimative "TV b gone"  :-DD

Imagine a charger like this in an consumer electronic market.
Title: Re: EEVblog #1092 - Wi-Charge IR Wireless Charging - Fact or Fiction?
Post by: hans on June 07, 2018, 08:22:29 am
Class 2 laser classification is drawn at 1mW. Even at that power level, it assumed that the blinking reflex of the eye prevents long exposure. When you suppress that reflex then damage could appear. Unfortunately the eye reflex doesn't work for infrared, so you're directly exposed. I wouldn't though any infrared laser without a good pair of laser glasses.

If they are transmitting a couple of Watts of light continuously out and 1mW is the safety threshold, then just a reflection of 1:1000 power is enough for some serious trouble. Basically anything that does not create a diffuse reflection is a problem.

Maybe they use the most diffuse laser beam they can get away with, but I highly doubt given the very small area of the device light panels.

I agree with the argument in the video. This seems to be an excessively expensive, complex and potentially dangerous solution that is solved with a 20$ powerbank and a simple charging routine. Or just put a freaking outlet where you need power.
Title: Re: EEVblog #1092 - Wi-Charge IR Wireless Charging - Fact or Fiction?
Post by: nctnico on June 07, 2018, 08:42:52 am
Couldn't resist...
(https://media.makeameme.org/created/Prepare-the-Laser.jpg)
Title: Re: EEVblog #1092 - Wi-Charge IR Wireless Charging - Fact or Fiction?
Post by: EEVblog on June 07, 2018, 11:21:13 am
If they are transmitting a couple of Watts of light continuously out

They have to be doing that to deliver 5W continuously, it's a basic law of physics. In fact it's likely in the order of 20W optical power at least. They have basically admitted to me it's at least 11W optical.
Title: Re: EEVblog #1092 - Wi-Charge IR Wireless Charging - Fact or Fiction?
Post by: EEVblog on June 07, 2018, 11:26:50 am
This is hard to believe, both because the receiver looks like a simple solar cell

And that's another thing I forgot to mention in the video.
The patent mentions retroreflectors, and a previous prototype does that, but I'm not sure if the latest one does.
Their entire concept from day one was doing away with one mirror in the traditional laser cavity and using the retroreflector in the receiver to complete the cavity. i.e. it becomes an "external cavity" laser.
The idea is that if you break that external cavity beam, the laser effectively automagically shuts of instantly.
Scatter is still a major danger though.

(https://i.imgur.com/tXfTZsf.png)
Title: Re: EEVblog #1092 - Wi-Charge IR Wireless Charging - Fact or Fiction?
Post by: maxwell3e10 on June 07, 2018, 11:50:25 am
The idea is that if you break that external cavity beam, the laser effectively automagically shuts of instantly.
Semiconductor lasers have a large intrinsic gain so they would emit a lot of spontaneous emission light even without a cavity and even if they have a very high quality anti-reflection coating on the output facet. One would only get a factor of 3-5 reduction in power when the retroreflector is blocked, not much more.
Title: Re: EEVblog #1092 - Wi-Charge IR Wireless Charging - Fact or Fiction?
Post by: StillTrying on June 07, 2018, 12:29:04 pm
Their entire concept from day one was doing away with one mirror in the traditional laser cavity and using the retroreflector in the receiver to complete the cavity. i.e. it becomes an "external cavity" laser.
The idea is that if you break that external cavity beam, the laser effectively automagically shuts of instantly

I don't think anyone believes an "external cavity" laser exists, I certainly don't.

I've watched the linus vid again closely, I think there's a chance it's faked!
Title: Re: EEVblog #1092 - Wi-Charge IR Wireless Charging - Fact or Fiction?
Post by: SMB784 on June 07, 2018, 05:53:01 pm
This is hard to believe, both because the receiver looks like a simple solar cell

And that's another thing I forgot to mention in the video.
The patent mentions retroreflectors, and a previous prototype does that, but I'm not sure if the latest one does.
Their entire concept from day one was doing away with one mirror in the traditional laser cavity and using the retroreflector in the receiver to complete the cavity. i.e. it becomes an "external cavity" laser.
The idea is that if you break that external cavity beam, the laser effectively automagically shuts of instantly.
Scatter is still a major danger though.

Howdy Dave,

Your point about safety is in fact the most salient reason why this device cannot ever come to market, and likely doesn't actually exist.

I did a couple of back of the envelope calculations (that I will show tomorrow) that demonstrate that this thing would far outshine the sun if it hit any surface, and it wouldn't even be visible due to the NIR nature of the laser, so you would have no idea that you were going blind until it had already happened.

I wouldn't even be able to get safety clearance for this device in my laser lab; there is no way this device is FDA cleared for anything other than some R&D environment, and if the video is actually a real prototype at the stated specifications, the poor man in the video is now almost certainly blind.
Title: Re: EEVblog #1092 - Wi-Charge IR Wireless Charging - Fact or Fiction?
Post by: G7PSK on June 07, 2018, 06:48:05 pm
A 5 KW laser will cut through 25mm of steel (https://www.msslasers.com/used-lasers-for-sale/trumpf-5030-fiber (https://www.msslasers.com/used-lasers-for-sale/trumpf-5030-fiber) ) so what damage will 20 watts do, it should be able to cut tin foil.
Title: Re: EEVblog #1092 - Wi-Charge IR Wireless Charging - Fact or Fiction?
Post by: EEVblog on June 07, 2018, 07:05:13 pm
I've watched the linus vid again closely, I think there's a chance it's faked!

I greatly doubt it's fake, but it's almost certainly a highly engineered demo, likely one that needs some potential massaging to get working.
In fact it's not new, they have had the speaker and train demos for a long time now.

http://www.youtube.com/watch?v=R-XcD_aVfmo (http://www.youtube.com/watch?v=R-XcD_aVfmo)
Title: Re: EEVblog #1092 - Wi-Charge IR Wireless Charging - Fact or Fiction?
Post by: janekm on June 07, 2018, 07:26:33 pm
This blog which is linked as the official blog from the wi-charge site has a curious article today: https://chargeguy.blogspot.com/2018/06/is-line-of-sight-required-for-wireless.html

Suggesting that using reflections off random surfaces in the environment to overcome obstructions would be practical for the wi-charge solutions seems a little odd (though it would kind of mesh with the free-space laser concept, but hard to imagine that would work bounced off of other surfaces, not to mention the issue of scattering...)
Title: Re: EEVblog #1092 - Wi-Charge IR Wireless Charging - Fact or Fiction?
Post by: apis on June 07, 2018, 08:25:58 pm
What if you put a small reflective object, like a needle, onto the receiver while it is charging. Instant blindness (from the reflections)?
Title: Re: EEVblog #1092 - Wi-Charge IR Wireless Charging - Fact or Fiction?
Post by: madires on June 07, 2018, 09:00:47 pm
Using reflection would decrease the efficiency dramatically more. The surfaces of your furniture and walls have different reflection factors (from absorbing up to full reflection) and the reflected IR will be spread even more, i.e. less power per area. Some people think that they can ignore basic physics. :palm:
Title: Re: EEVblog #1092 - Wi-Charge IR Wireless Charging - Fact or Fiction?
Post by: Psi on June 08, 2018, 06:50:13 pm
I've watched the linus vid again closely, I think there's a chance it's faked!

I greatly doubt it's fake, but it's almost certainly a highly engineered demo, likely one that needs some potential massaging to get working.

Yeah, i made a thread recently showing just how efficient you can get precious metal brushed DC motors.
12VDC motors that have enough starting torque from 65mV input.
http://www.eevblog.com/forum/chat/post-a-guess-on-the-min-starting-voltage-for-this-brushed-dc-motor/msg1560541/#msg1560541 (http://www.eevblog.com/forum/chat/post-a-guess-on-the-min-starting-voltage-for-this-brushed-dc-motor/msg1560541/#msg1560541)

I'm sure you could make a train using those kind of motors combined with really high quality ball bearings on the wheels.
You'd end up with a train that moves from a really small amount of energy, compared to a normal toy train, but at ridiculous cost.

Title: Re: EEVblog #1092 - Wi-Charge IR Wireless Charging - Fact or Fiction?
Post by: lem_ix on June 08, 2018, 09:07:25 pm
Power and lasers, what could possibly go wrong  |O Blinding people aside, I wonder if this tech will end up in a completely different field.
Title: Re: EEVblog #1092 - Wi-Charge IR Wireless Charging - Fact or Fiction?
Post by: fatboy77 on June 09, 2018, 12:08:06 pm
Yeah i find the trains in all videos i saw are too stable considering they have no batteries inside...
The testers should show us IR glasses view or PIR or something :)
Keep up the good job!
Title: Re: EEVblog #1092 - Wi-Charge IR Wireless Charging - Fact or Fiction?
Post by: NiHaoMike on June 09, 2018, 01:50:35 pm
What if the light source is not a laser but a conventional light source like LEDs or even incandescent bulbs? 250W heat lamps are easy to get off the shelf and are relatively safe to use.
Title: Re: EEVblog #1092 - Wi-Charge IR Wireless Charging - Fact or Fiction?
Post by: SebastianCurefab on November 15, 2018, 11:56:11 am
Hi all,

released in September or October 2018 there are some papers with actual numbers and graphs for tech-savvy people.
The end-to-end-efficiency is about 10%-20% with an additional 4W-5W lost (if I interpret them correctly). Not bad!

https://arxiv.org/pdf/1801.03835.pdf (https://arxiv.org/pdf/1801.03835.pdf) (Fig. 23)
https://arxiv.org/pdf/1802.01570.pdf (https://arxiv.org/pdf/1802.01570.pdf) (Fig. 4)
https://arxiv.org/pdf/1809.09364.pdf (https://arxiv.org/pdf/1809.09364.pdf) (Fig. 11)

The actual optical window of the receiver is just 15x15x6 mm in size, the rest is electronics (e.g. voltage conversion).
Source: http://www.wi-charge.com/sep-2018-webinar-on-integrating-wireless-charging/ (http://www.wi-charge.com/sep-2018-webinar-on-integrating-wireless-charging/)

A photovoltaic cell is used below a diffusor below the output beam of the receiving mirror. So the complete area of the PV cell is used.

The technology can be improved with better PV cells, greater distance, faster switching (they state it activates in 2s, but can be much improved).
What if they use a wavelength which goes through the body?

Best regards,
Sebastian
Title: Re: EEVblog #1092 - Wi-Charge IR Wireless Charging - Fact or Fiction?
Post by: StillTrying on November 16, 2018, 03:12:52 am
https://arxiv.org/pdf/1801.03835.pdf (Fig. 23)
https://arxiv.org/pdf/1802.01570.pdf (Fig. 4)
https://arxiv.org/pdf/1809.09364.pdf (Fig. 11)


All them graphs and calculations haven't convinced fooled me!

"What if they use a wavelength which goes through the body?"

Beamed X-rays could allow non-line-of-sight charging. >:D
Title: Re: EEVblog #1092 - Wi-Charge IR Wireless Charging - Fact or Fiction?
Post by: EEVblog on December 01, 2018, 12:09:27 am
They have a new dev kit, I wonder if they'll send me one?  ;D
https://www.netans.com/2018/11/19/wi-charge/ (https://www.netans.com/2018/11/19/wi-charge/)
Title: Re: EEVblog #1092 - Wi-Charge IR Wireless Charging - Fact or Fiction?
Post by: StillTrying on December 01, 2018, 01:54:46 am
There must be all kinds of interesting tech stuff involved in their high power Open Cavity Scanning Laser, but it never gets mentioned anywhere, I don't think they realize or know what's involved!

I'm afraid I still think it's faked with just PV cells.