Wireless Electricity Update

wireless electricity update

I have been following wireless electricity in this blog for some time now, through these previous posts:

Wireless Electricity Update Summer 2009, and

Wireless Electricity (multiple updates within)

Here’s the most recent installment of news on the topic.

It looks like the folks at WiTricity, of whom I am their biggest fan, in Massachusetts are well on their way to having a commercial wireless electricity product on the market within the next 12-14 months. Based on this timing it will just miss the 2010 Christmas shopping season.

I wonder if this is a commercial product that can then be integrated into other manufacturers devices through OEM arrangements (ie: iPhone, now compatible with WiTricity for wireless charging) or a direct consumer device that you can either purchase individual device interfaces for or that will have multi-connector functionality built-in. Since the whole point of wireless charging is about removing chords and the concept of proximity of devices to power sources I hope they are able to offer individual device interfaces at launch and then eventually become so important to the market that they will get the OEM arrangements, like BlueTooth has done.

Considering the fact that people use chord-based charging stations to power up their mobile devices now, the move to wireless electrical charging will also cause a new problem which is “I can’t find my [insert device name].” When it comes to cell phones you will at least be able to call your phone, assuming it isn’t on vibrate, to locate it within your house since the battery won’t be dead… as long as you’re a member of the younger generations who never turn their mobile phone off. It amazes me how often my parents and those of their generation (early sixties now) still turn their mobile phones off at various times. Anyway, my point is that for devices other than mobile phones (battery powered vacuum cleaners, lawn mowers, and especially smaller ones like watches, hand-vacs, etc) an audible locating feature might be a great addition. You could use a central WiTricity panel to cause each device to beep at you for a bit to remind you where you hid it last.

The WiTricity system sounds like it will give you enough freedom to fully misplace your items without any concern of them losing a full charge. What a fun problem to have.

Wireless Electricity Update Summer 2009

This is an update on recent developments in wireless electricity. I’ve been writing about wireless electricity for several years now and have corresponded with Marin Soljacic at MIT on one occassion regarding his progress as well.

The MIT Technology Review is doing a good job of following along with the race between their team (now operating within the independant VC funded startup WiTricity) and Intel (who appears to be building on top of some of their own technology) to bring a wireless electricity product to market first . Thanks to my buddy Jim for pointing me to this article last week. The article talks pretty much all about Intel and their June 18th presentation at the Computer History Museum in Mountain View, California. At the event they showed a wireless electricity prototype which charged an iPod speaker at a distance of one meter using a 60 cm diameter loop transmitter and a 30 cm diameter loop receiver both tuned to a frequency (electrical current oscillation) of seven megahertz. Electrical power was transmitted with 80% efficiency through the specific arrangement they demonstrated.

This display is similar to one they showed in the Fall of 2008 which lit a lightbulb over a similar distance with only slightly less (75%) efficiency. Because of the small improvement in efficiency (5% increase in 10 months) I wonder if they are approaching a unique design limitation or a fundamental limitation with the transfer of a magnetic field through the air. It’s also worth wondering whether the 20% of energy lost is falling out as the magnetic field passes through the air (currently a distance of one meter) or through the process in which electric energy is converted into magnetic energy and back within the wire loops that comprise the transmitter and receiver. I figure the magnetic field transfer through the air is to blame for most of the energy lost in this model. Does anyone know?

I also haven’t heard anyone talking about efficiency gained or lost when a single transmitter is used in combination with multiple transmitters. If a transmitter is able to send a magnetic field out in multiple directions (which I don’t know if it does) then it seems to me that a receiver in a location far away from another receiver would not reduce the ability of the other receiver to be driven by the magnetic field. Could this technique be used to increase efficiency to a level that the current energy losses would be more than compensated for? I don’t see why this wouldn’t work… but my physics knowledge is based mostly on Physics 26 and 27 in the undergrad program at UNC from eight years ago 🙂 At least the classes did include sections on electricity and magnetism.

Another note about WiTricity, the company pushing MIT’s research forward that I mentioned earlier, their website contained a few things I found interesting:

1) It mentions that WiTricity has an exclusive license to the wireless electricity prototype intellectual property developed by Marin Soljacic and his team at MIT. There are also some other interesting details on the about us page of the WiTricity website as well.

2) It contains a nice illustrated description about how wireless electricity works which is a great read for a wireless electricity novice and probably great content for a lesson plan if you are a teacher.