Wireless Power Transmission

This is great but it is not a new idea. A lot of people already use that just at a smaller scale. Your expensive rechargeable toothbrush does the same thing. One coil is energized (the charger) and than the coil inside the handle of the toothbrush is also energized by the magnetic field created. It seems like they were doing the same thing just with bigger coils. I don't want to seem like I'm putting it down because I've been hoping somebody would come up with something and this is a step in the right direction.

You could argue that a simple transformer does the same thing. I think the key here is the ability to transmit power over several feet and still maintain 40% efficiency.

I bet they come up with 40% by careful adjustment and it is 40% of the radiated power. A typical transmitter at 10 Mhz may be only 50% efficient at a few hundred watts power out, which cuts it to an overall 20%.

But it is encouraging to read

Nikloa Tesla patented the wireless transmission of electirc power over a century ago.

Guest is correct, but how do you charge for it? Also, do you want to be soaking in hundreds of volts of high frequency energy all day? I think you already get enough juice from radio transmitters.

Are they getting grant money for this? What about the cord going to the power coil? Oh god, please don't make me look at it!

John

This forum was recently discussed to death in another CR4 blog.

It will not be viable for several reasons, one being the appalling efficiency, the other being that most people would not want to live in such a strong electric "Smog"....

Although it might be "kinda neat" to be able to charge your phone wirelessly, I can't imagine it ever being efficient. If you had such a charger in your office, it could be topping up your laptop and phone while you sit there, eliminating the need to remember to take the phone out of your pocket to charge it. So it could sell on convenience alone, but I hate to see efficiency go down the toilet. And am I utterly and totally convinced that being bathed in even more high intensity energy is a good thing? No.

Odd that the norm for cell phones is to plug the charger into the phone, but for home remote phones you just set the unit on its charger, which is quicker and more convenient.

Ken, you wrote:-

Odd that the norm for cell phones is to plug the charger into the phone, but for home remote phones you just set the unit on its charger, which is quicker and more convenient.

It actually depends on the model and age of your handy, Nokias over 5 years old for example were originally supplied with a cradle as well....the norm today appears to be plug in as you mentioned, sad really!!

It would be interesting to hear of modern phones that have a cradle......

wireless power transmision comes in handy with older age, anyway not with the same detrimental effects as for youngsters who are looking forward to have a family, if you know what I mean...

Sos ya want free power, huh? Here's a little trick that you urbanites can play with...

It seems that in urban settings there's an awful lot of AC flying through the air at all sorts of frequencies - AM stations, FM stations, power line noise, etc.. Anyway, so this guy I know took a germanium diode and a couple of capacitors, wired them together, and hooked the diode to about 50' of wire. The propose of the circuit was simple, receive as much AC as possible and rectify it into DC. If I remember correctly, he got about 5 Volts out of the thing - yes, for free, minus parts.

While I can't remember the exact circuit design, I'm sure there's enough electrical talent out there to design an identical circuit in no time. Try it out!

I heard about a guy who did this for while next to a radio station. He caused a propagation pattern disturbance and got charged and fined for it,

This was no where near a radio station... Here's the long story.

This guy, connected with the Exploratorium had received a small grant from the USGS because he had an idea about predicting earthquakes. He made several of these circuits and connected them to PCs throught the Bay Area - he picked my house for a site for some reason. The PC would record the voltage over 24 hours, then dump it to a floppy. Once a month, he'd come by, collect the floppy and replace it with another.

The weird thing about where we were located (landfill) was that the collective signal power would rise and fall with the tides in the Bay. A five foot hole in the ground would ebb and flow with bay water. Anyway, after all of his data crunching, the USGS gave him money for more sophisticated equipment, which he deployed in more realistic areas. That was the last I heard of his research. However, the circuit created a surprising amount of power. And could have been used for all sorts of toy-like projects.

Now, if I created a very large inductor and capacitor tuned to 60 Hz, and aligned it to the power lines going down my back fence, I'm sure the power company would pick up on that real fast!!!

I've thought along those lines too. The earphone connected to a crystal (diode) radio is a tiny linear reciprocating motor... so given enough antennas, you could RULE THE WORLD (cue diabolical laughter)!!!

Of course, if I built such a thing, the joke would be on me if it turns out that I am picking up stray currents from my own in house AC wiring.