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Matt
04-09-2008, 03:55 PM
Am I wrong in thinking that these devices will waste tons of energy in the process of turning it into radio signals? I mean, the house demo shows one plugged into the wall just "spraying" energy waves in every direction all the time. Isn't that like setting your potted plant in the middle of the driveway and trying to water it with a sprinkler 20 feet away?

http://www.powercastco.com/index.php?page=downloads
http://www.powercastco.com/index.php?page=cesMovie

Sienna
04-09-2008, 04:46 PM
Several things worry me with "wireless power"...

1) Why didn't the camera get close? Usually, if you are going to give a demo, you want the audience to see whats going on.
a) It could be a simple answer, that interviewer doesn't have a cameraman.
b) It could be that the wireless power table was giving off lots of radiation that affected the camera (notice also there was no wireless mic).

2) How does the base station detect the presence of a device? I really don't want this thing losing watts of power all day every day for no reason.

3) What frequency do these devices operate on? What harmonics are going to be caused by this? Is it going to knock out things like WiFi?

Eric
04-09-2008, 08:51 PM
Oh I soooooo have to throw my 2 cents in on this one!!! (simply because I come from broadcast tv)

1) Why didn't the camera get close? Usually, if you are going to give a demo, you want the audience to see whats going on.
a) It could be a simple answer, that interviewer doesn't have a cameraman.
b) It could be that the wireless power table was giving off lots of radiation that affected the camera (notice also there was no wireless mic).

Much simplier answer. They were at the show and they were looking for a cheap way of doing some potential marketing. There was no cameraman. Just a tripod and a little consumer camera. And if you notice the guy... he's not a reporter (far from it!) This is how it probably happened. They were at the show and they asked someone in the company to bring the in-house camera and do a little mock interview. "Maybe we can come up with a use for it" was probably asked. So a quick, dirty, easy way of saying... here's the product and look! We're at the show.
Now the second video was shot HD or 35mm film.(many prod. companies still do shoot film believe it or not). They even had a steadicam. Major bucks. The must use that for their sales presentations.


2) How does the base station detect the presence of a device? I really don't want this thing losing watts of power all day every day for no reason.

Al Gore must love this product. So much for being green. You're both correct, the power loss in transfer has got to be huge! I think there is more hype in the use than pratical application. But I could (and have) been wrong before.
Now with that said... if you can "directional-ize" it, and have the device tell you when it's in range with bluetooth or similar technology (or RFID)... then you may have something, but the power loss would still be great.

Matt
04-10-2008, 09:45 PM
You all echo my suspicions. As cool as this technology appears it's just not really reasonable. Especially in a world where we need to move toward conservation. I could see it for recharging small devices when in close proximity, but not much more than that.

Adrenalynn
04-11-2008, 02:45 PM
I hate to be the odd one out here, but I'm not so certain it's as bad as "all that".

The concept of induction power isn't new. I see nothing but low-current devices being charged there. I also see that the devices are logo'd for powercast, suggesting that they are built for the system.

There's a tremendous amount of waste-current going into induction heating anyway, just take a cheap induction probe near any outlet in your house to see that. Because the devices are built for the system, it'd be trivial to establish a link between the charger and devices prior to amplifying the induction current, and subsequently "broadcasting" it. No device in range? No additional power requirements. Device fully charged? Don't amplify the power.

I haven't searched their patents, but it doesn't seem logical that they'd overlook a concept as simple in the design.

Let's not forget that your 802.11 router is radiating large amounts of [typically] wasted power. So's your cell phone. So's your cordless phone when it's off the base laying there on the sofa.

They also have FCC approval. Going through the process repeatedly in my current "real job", I can say that getting FCC approval on anything that transmits a signal and may come near to being thought to possibly contact a human is non-trivial. I currently do Digital Cellular (EVO), GPS, Assisted-Fix tracking devices. Unless they convinced the FCC that it's never going to be closer than 20cm+ to exposed skin (and when the guy picked-up his bluetooth handset, for example, he was a lot closer than that), they had to go through SAR (Specific Absorbtion Rate) testing, proving that it was safe for human consumption. And that means very low power.

Again, just off the cuff, I visualize it using very small amounts of waste-power to selectively trickle-charge batteries. In that application, I think it may have some merit. And must be of interest to robot builders. When your 'bot gets "bored", it just needs to find a transmitter, sync, and charge...

Droid Works
06-02-2008, 08:24 AM
There has to be some health issues also. This is not a new idea it has been tried before, But there was no safe way to do it that wasn't harmful to humans.

ScuD
07-31-2008, 07:41 AM
If there are health issues involved in this, the same applies to cellphones. And Wifi. WiMax, the local radio station, your microwave, the overhead fluorescent light, the power cables running through the wall, and even the earth's magnetic field itself.

Anything will kill you, it's just a matter of how fast :happy:

Although it's never been proven, I think Tesla had advanced a lot further in the field of wireless power transmission.
I don't think it involves the Tesla coil though..

ooops
07-31-2008, 08:06 AM
Healthy or not for humans, I just wish they were publicly traded.
I hear a chi-ching in their future.

Adrenalynn
07-31-2008, 11:22 AM
Thank you, ScuD!

Electricity
07-31-2008, 11:36 AM
This thread smells of old.. :p

I just read an article about this technology recently in some magazine, and I had some of the same questions. How can it be healthy to walk around in a house thats charged up like that?
Also, the second video was kind of funny, things that where supposed to be wireless weren't.. like the computer screen, or the 2nd lamp..

ScuD
07-31-2008, 11:52 AM
Putting aside the discussion of whether or not it's bad for your health for a moment, my point was that we are constantly immersed by (electro-)magnetic fields these days.
There's just no way around it. Period. If someone complains about radiation from a cell-phone antenna, I feel they're being hypocrites unless they want to return to the 1800's.

Technology and "comfort" comes with its price, as noted before on several occasions, there's no free lunch.


Now, back to the health part of the matter.
At work I spend about 70% of my time in the lab. It's a confined space, usually around 28C with the airconditioning on, screamingly loud with the sound of serverracks / computers / hot-air soldering irons / frantic colleagues, and last but not least it's buzzing with radiation.

At any given time during the work day, there's probably more than 30 devices emitting power at 32 dBm at 900Mhz, going up in frequency but dropping in power (24dBm at 2.1GHz eg.)

Since I've been working there, I have noticed that I suffer from more migraine attacks. But then, I noticed they don't occur unless I sleep at my GF's who has a really soft bed...

Ok, way too long post, but these things tend to get to me :happy:

Alex
07-31-2008, 03:17 PM
This thread smells of old..There are no worries about bumping old threads here in the TRC. In fact, it's kind of encouraged:D We know there are a ton of oldies but goodies here. If someone that has some knowledge/experience in a topic they come across that is several months old, by all means, bump it! Now, if someone is bumping a thread, just for the sake of bumping a thread, that's a different story. Bumping a thread if a question hasn't been answered in a reasonable timeframe is cool. But, if someone asks a question, then 2 hours later bumps it because they believe they believe they are not gettting their answer quick enough, then I would consider it inappropriate. Also, bumping a thread with adding "garbage" is not cool either.

If anyone would like, I can post a sticky about this in the Off Topic forum to send people to and remove this post since it is a bit "hijackish":)