Re: [LAD] Wireless Electricity vs audio quality - Linux-audio-dev

27 Aug 2008

Dan Mills wrote:
...
  On Tue, 2008-08-26 at 13:07 +0700, Patrick Shirkey
wrote:

  They demo'd a 60w light bulb which they said
could get 80% efficiency 
 upto 3 feet. They are expecting to increase the distance as the RnD 
 progresses. You can expect the transfer efficiency and power rating to 
 increase with time too.

 They demoed a 60W lightbulb in a laboratory environment, there are lots
 of things you can do under those conditions that just plain don't fly in
 the real world. 

 In a sufficiently well screened room with RF reflective surfaces, many
 things are possible. 

I don't see how there was any room for the reflective surfaces in the 
hall to have an impact on the amount of energy received by the bulb. 
There was only three feet separating the transmit/recieve points.

...
   The guy at MIT
who designed the circuit has been on record saying it 
 will not interfere because the coupling is done at a very specific 
 frequency.

 That don't help when there are non linear junctions in the area.... 

 I call him at best semi competent at either analogue design or design
 for emc. Further the occupational limits for non ionising radiation
 would (at least in Europe) surely kill this thing.  
Everyone has cellphones even though the health hazards are still largely 
unknown. Cigarettes are still legally available too. I don't see why 
they will stop this technology from coming to market if it has the 
support of the industry behind it. This particular circuit was first 
made public about 18 months ago and now that Intel are actively pursuing 
it I don't think it will be long before Sony, Samsung, Toshiba, 
Phillips, Apple et al get behind it too. After all Apple get a lot of 
their new technology from these guys and are using Intel in all their 
latest PC/notebook lines.

...
  I could also see
 serious issues with induction heating of any highly conductive materials
 bought into the field, it don't need to be resonant for eddy currents to
 heat it.  

    I'm agree that this is a serious concern that needs to be addressed but 
from what I have read they are pretty specific about it not being a 
problem. This may be along the same lines as the Large Hydron collider 
creating a black hole to consume the solar system.

...
    It
 will never work well over any distance as the inverse square law applies
 once you are out of the near field of the aerial (A tuned loop from what
 I can see - also very old technology), this distance depends on both
 wavelength and loop dimensions, so making the loop smaller will not
 improve things).    

 I believe Tesla would have had a word to say about the above statement...

 Well, if you want to play appeal to irrelevant authorities, then Maxwell
 would I think agree with my position..... 

    Sure and Edison would probably too.

...
  The thing is a cool demo of an air core resonant
transformer with a
 somewhat high leakage inductance, (and I suspect an automatic matching
 and tuning network) but IMHO that is all it is.  

 That demo had the look of the canonical 'trade show demo' to me (don't
 look behind the curtain). I don't really see much to get excited about
 here and there does not to me seem to be anything really new. 

I certainly agree that they had most likely adjusted the environmental 
conditions to there favor for the demo but from where I stand if/when 
this tech becomes available for the industry we will definitely be 
incorporating it into our products.

-- 
Patrick Shirkey
Boost Hardware Ltd.