In far field zone (high frequences, bluetooth, wifi) it captures part of already emmited wave, so it doesn't place additional load on emitter directly. But since device blocks wave propagation through itself if placed between transmitter and receiver it will degrade reception. And that in turn can result in automatic increase of transmitter power (in case of GSM phones at least). Which will increase transmitter consumption.
On the other hand, if you stacked 20 or 30 of these around your ~100mW wifi basestation, where do you suppose the power extracted comes from (and, as you suggest,what do you suppose would happen to your wifi range? I also suspect loading up the transmitting antenna like that will change enough about the way the transmitter/antenna system works, and degrade the transmitter output in even more serious ways than just the raw power extracted might indicate - I'l guess the frequency and resonance assumptions made by the transmitter designer would all be wrong.)
Faraday's law of induction: A changing electric field through a coil induces a current in that coil. Induction is how transformers work. Hopefully you believe that attaching things to a transformer's output can put a load on its input.
Since this device and transformers both use induction, if it can happen in a transformer, it can happen with this technology.
However when you read the announcement of the university itself you learn that he was awarded the price in digital media because:
> "Dennis Siegel thematisiert die sich überall befindenden elektromagnetischen Felder[...]"
> TRANS: Dennis Siegel thematizes the everywhere occuring electromagnetic fields)
> "Die Jury hat an dieser Arbeit den feinen Humor der Arbeit, den gedanklichen Kurzschluss, die Fähigkeit zum konzeptuellen Brückenschlag, die sensible einfache Gestaltung sowie die Zukunftsorientierung des Projektes hervorgehoben und überzeugt"
> TRANS: The jury has emphasized and was convinced by the fine humor of the project, the mental short circuit [it's not clear what this refers to in the announcement], the ability to create conceptual bridges, the sensible simple design and future-orientation.)
After reading this announcement one might actually come to the conclusion that this an art project and that the fact that a student created a device that charges batteries using electromagnetic fields by itself is rather boring and irrelevant. The fact that any high school student should have the necessary theoretical knowledge to built such a device could also be a give away.
Didn't even bother click, came here to read comments instead.
Can HN please ban Physorg like everyone else?
I prefer the "fluorescent tubes under transmission tower lines" demonstrations. Here's one link (http://hacknmod.com/hack/field-of-fluorescent-tubes-powered-...) but there are others.
It's neat to be able to do. I'm pretty sure the energy harvested comes nowhere near the energy used to create the parts, or assemble the device.
If you want to make a really simple demonstration that "there's power in the air" you could try this experiment - light an LED from cell phone frequencies (http://www.creative-science.org.uk/mobile_LED.html). (Good Luck getting an OA91 diode, though.)
This is cool but I'd be worried if it caught on in any sort of scale.
I think the resulting resistivity and wasted electricity would make it unfeasible for mass usage over distances even if it had been funded to completion.
I wish portable device OEMs would adopt inductive charging more though. No worrying about cables or broken ports.
Given this simple and obvious observation, the fact that phone manufacturers have mostly dropped proprietary charging interfaces in favor of USB seems like a minor miracle.
More likely because this is hardly a new idea and people have been doing this for decades. I remember reading in an elementary school science book how some farmers used to run fences under power lines going through their fields to get some "free" energy out of the electrical grid. This did not go over well with the electricity utility.
It's perpetual motion nonsense to suggest mounting these on roofs to power buildings.. Apparently phys.org is as bad as new scientist!
> He's won a 2nd place award in the HfK Bremen Hochschulpreis 2013 competition for Digitale Medien, for his efforts.
Who on Earth won first place?
It would be quite in line with German culture for somebody to have no qualms about lying for the purpose of calling public attention to some perceived environmental threat or health risk (think the Green party scaremongering against genetically modified crops using flourescent dyes) and then saying it was all art for a good cause if called out on it.
You claim that publicly lying is part of the German mentality?
Whether or not the view I expressed is rubbish, I believe the term "prejudicial" is applied incorrectly here. My opinion of the German environmentalist movement and the methods that are considered appropriate within it is certainly harsh and judgmental, but it was formed in a long process of disillusionment from an initially sympathetic position I had for them.