Hexus - minor let down on the news front IMO

[Andeh13]

This might just be me, but reading the article on the new Dell Latitude Z made me really stop & think...all to do with wireless charging.

I see this as a massive massive leap forwards, being able to charge laptops, mobile phones...anything which has a battery wirelessly, and yet the first news we hear about it is via a press release that Hexus has copied across? Surely something like this deserves its own news story with the specs, abilities & devices which will be capable...and when we could expect them?

Fair enough Hexus is computer orientated, but am I the only one seriously impressed with this new technology?

[mmh]

I'm sure i read about this on hexus a long time ago, when the technology was being pioneered... i havent heard anything about its commercial usage until this either though...

[DeludedGuy]

I’m a little sceptical about wireless charging; I’m not in the know, but surely it dissipates more energy through the air then say, a copper cable.

I'm probably wrong, but in today’s world of energy efficiency this may be a step backward just for the sake of convenience.

[TheAnimus]

There is the Inverse Square Law which you might have come accross in physics/electronics a-level or uni.

So yes there is a power loss, however these guys claim they have been able to use some resonance to stop the loss been so great. My physics ain't good enough to understand, what with me dropping the a-level 7 years ago!

But even if its just a 15% power loss, for the sake of not having a wire on the table?

WTF people..... WTF.

[Steve]

I believe we're chatting to Dell about the new laptop so may have some more info for you in due course.

[bsodmike]

There is the Inverse Square Law which you might have come accross in physics/electronics a-level or uni.

So yes there is a power loss, however these guys claim they have been able to use some resonance to stop the loss been so great. My physics ain't good enough to understand, what with me dropping the a-level 7 years ago!

But even if its just a 15% power loss, for the sake of not having a wire on the table?

WTF people..... WTF.

Considering wireless charging would be achieved by essentially two solenoids (the charger and one on the device) where the flux linking with the devices circuit induces an emf. Of course, unlike a typical transformer, which has a soft iron core linking both the primary and secondary coils, there will be an air gap between both the 'primary' charge solenoid and 'secondary' device solenoid. The amount of fluxed linked would be much less than in a 'closed iron circuit' if you will and it is the product of the number of turns and the rate of flux linked that determines the induced emf.

The size, especially of the coil inside the laptop, could pose certain engineering challenges considering the 'real estate' inside laptops these days are quite limited.

While the inverse square law comes into play, if one were to have a laptop placed on top of a charging station (which let's say doubles as a dock etc) it shouldn't be such an issue? Of course, on the laptop end the received emf needs to be rectified back to DC and generating the 2-3A that most laptop batteries need for charging is quite straightforward (stepping down the voltage from the charger plate to the laptops coil which would have less turns). The AC voltage induced in the secondary inside the laptop could however cause interference with the operation of the laptop, depending on its frequency etc.

Oh yes, these coils do heat up quite a bit as well; I think keeping them cool might actually be a larger concern. You don't want the lappy going boom.

[scaryjim]

... the first news we hear about it is via a press release that Hexus has copied across? ...

There was a featured article from one of the tech shows last year about one exhibitor having a desk with demo wireless charging built in, and they showed several different devices (laptop / phone / iPod) charging from it.

You know, it's quite possible that Dell's press release was the first that Hexus has heard of it since that demo... most manufacturers would want to keep something like that quiet if they'd finally found a way of producing it commercially; gives them a competitive edge...

[funke_munke]

Like sitting outside someones house and pinching their wireless connection - is anyone thinking about sitting outside and charging their phone?

[TheAnimus]

Oh yes, these coils do heat up quite a bit as well; I think keeping them cool might actually be a larger concern. You don't want the lappy going boom.

I've not put that much thought into it I grant you, but I imagine the gap has to be over 5mm.

My understanding of a wound transformer was the closed core played a vital part in conducting the flux?

As such wouldn't there be a HUDGE loss if there wasn't a constant iron core?

[Zhaoman]

Like sitting outside someones house and pinching their wireless connection - is anyone thinking about sitting outside and charging their phone?

Haha - would probably take several lifetimes but yeah sounds like a good plan. Does anyone else have the suspicion that having that thing will slowly fry you if you're sitting near it? Should it not have some sort of shielding to prevent it 'charging' your balls...?

[bsodmike]

I've not put that much thought into it I grant you, but I imagine the gap has to be over 5mm. My understanding of a wound transformer was the closed core played a vital part in conducting the flux? As such wouldn't there be a HUGE loss if there wasn't a constant iron core?

You are correct; in my first revision I did mention the need for a soft iron core (which tends to boost the amount of flux by around 50,000 compared to an air-core; but due to space restrictions would having an iron core even be practical?

Without a soft iron core, it is going to be quite difficult to get this to work in the first place but it could be achieved if the two air-core coils are very close to each other, < 1mm gap. This would however call for the coils to be impregnated into the outer surface of the casing though!

[bsodmike]

Haha - would probably take several lifetimes but yeah sounds like a good plan. Does anyone else have the suspicion that having that thing will slowly fry you if you're sitting near it? Should it not have some sort of shielding to prevent it 'charging' your balls...?

Only if you have balls of iron

[Zhaoman]

Only if you have balls of iron

oh jeez we'll not get into that one...

[bsodmike]

Does anyone else have the suspicion that having that thing will slowly fry you if you're sitting near it? Should it not have some sort of shielding to prevent it 'charging' your balls...?

oh jeez we'll not get into that one...

I was actually being quite serious. Electromagnetic induction is not the same as Electromagnetic Radiation (you can refer up the Electromagnetic Spectrum on-line for more details). EM-radiation is essentially a magnetic field perpendicular to an electric field and can be characterised by typical wave characteristics such as wave speed, wavelength, frequency, and phase. Visible light as we know it is one very small portion of the entire EM-spectrum.

You can 'shield' EM-radiation; Magnetic flux (or to be more correct, an electric field/emf) can be contained as well, via a Faraday cage, if needed but is not hazardous in the same way as EM-radiation. Flux linkage with a circuit works in a very different manner and is not a safety hazard, unless one has a incredibly high 'iron' content in their blood.

To protect the operation of the laptops internals from the 'secondary', everything else will need to be contained within a Faraday cage - from the mainboard, HDD, to the optical drive. When a computer case is grounded, it acts in a similar manner.

Don't forget the Earth also has its own magnetic field generated, with compasses pointing towards magnetic north