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Intel Claims an Advance In Wireless Power
Many readers are sending in coverage of a demo at Intel's developer forum of a wirelessly powered 60-watt bulb. The NYTimes gives background on Intel's improvement to the 'wireless resonant energy link' technology pioneered at MIT, where researchers achieved 50% efficiency of power transmitted several meters via magnetic fields. Intel reached 75% efficiency. Now they just have to make those coils a lot smaller.
This is not a new technology but it is helpful to have refined, although the first use when the technology matures will be short range devices (1-2ft) not long range devices (10-20ft).
A4tech made a series of wireless battery free mice that use the same technology (I've been using those for about 4 years)....they were cheap pricewise too. A4tech appears to have lost their sql server/domain (at a4tech.com), so I'm linking one from a shopping site:
http://www.ecost.com/detail.aspx?edp=39484911
These types of things are actually really nice, it makes the mouse extremely lightweight as well.
However, I seem to recall people saying the wireless transmission aspects will enable to create a "charging pad" whereupon you can place any device and simply charge it without having to connect it, and thus would be the basic use - put an ipod, a phone, whatever on said pad and charge ahoy.
You already have pulsating magnetic fields in your house. In the US, AC current is 60 hz, so you have a constant 60 hz magnetic field. That hum you hear is the oscillating magnetic field moving steel back and forth.
Your TV has a tremendous magnetic field, as do subwoofers.
The magnetic field won't hurt you. My dad was an electrical lineman for forty years, often working on the 30,000 volt towers. He couldn't wear a mechanical wristwatch because it would become magnetized. He just turned 77 and he's healthier than a lot of guys my age.
If magnetic fields caused cancer, linemen would die of lukemia right and left.
mcgrew's razor: Never attribute to stupidity that which can be explained by greedy self-interest
The house wiring doesn't create much field, electric or magnetic. You would have to be right next to the wire to use it.
Magnetic - The current going out the hot wire is exactly matched by that returning on the neutral. The fields due to the two currents cancel.
Electric - The hot wire has 120 volts on it and that would create an electric field but the neutral and ground wires are right next to it. That means the field, while not completely shielded, does not go very far.
OTOH: some appliances create pretty hefty fields. CRT TVs and monitors, motors and subwoofers come to mind. As long as you're willing to sit your calculator on an old CRT TV, you should be able to power it easily. ;-)
Exactly. My design back in 1992 had zero waste when an item was not near the mat. (I invented the "charge mat" for my final thesis for my EE degree.)
I simply looked for a change in inductance to detect if a device is local for charging, if so I switched from detect to charge and pulsed back to detect every minute. Also I did not have a 25% loss, but I was only supplying 10watts. (I was charging devices not powering them.) From what I remember losses went up ad the power range went up. Plus I used simple inductance not som fancy phased power system.
Side effect, keys on the mat will get warm, floppies and zip disks erased.
Do not look at laser with remaining good eye.