Freevolt - free energy again

[nali]

This one's a bit posher than your normal wacko... UK peer, Royal Institution etc 

http://www.bbc.co.uk/news/technology-34401616

At least he says it's for low power devices! 

[canibalimao]

Nowadays everything is free "anything".

«Get free money online»
«Get free energy from smartphone radiation»
«Free energy generators»

I'm still waiting for some "free sex-energy generator".

[wraper]

I'm still waiting for some "free sex-energy generator".

I'm rather for "free sex generator" 

[canibalimao]

I'm still waiting for some "free sex-energy generator".

I'm rather for "free sex generator" 

Good point. That would be a game changer also!

[tom66]

I don't see anything wrong with what he's claiming. It should be possible to harvest a couple microwatts of power, which is sufficient to power a low power sensor transmitting occasionally.  With the right matching network, and in nearby range of wifi and phones... I seem to remember a paper on this a while back which was able to get into the milliwatt range but only by modifying wifi router firmware and transmitting at over 1W.
 
Also, it wouldn't interfere with existing networks if it's only a receiver. Absorbing RF doesn't mean the transmitter has to pump more power out to compensate.  But apparently it's really easy to become a "mobile technology analyst" and claim things like that. Perhaps I should try that.

[BFX]

It's already lot of similar thinks on the web. It's possible. But only for devices that's no frequently used or when data from this devices is not necessary in expected time. Classic newspaper bullshit story    

[nali]

I don't see anything wrong with what he's claiming. It should be possible to harvest a couple microwatts of power, which is sufficient to power a low power sensor transmitting occasionally.  With the right matching network, and in nearby range of wifi and phones... I seem to remember a paper on this a while back which was able to get into the milliwatt range but only by modifying wifi router firmware and transmitting at over 1W.
 
Also, it wouldn't interfere with existing networks if it's only a receiver. Absorbing RF doesn't mean the transmitter has to pump more power out to compensate.  But apparently it's really easy to become a "mobile technology analyst" and claim things like that. Perhaps I should try that.

I guess for wearables they are counting on the user either having a mobile 'phone on them a lot of the time, or wandering about past other RF sources e.g. wireless routers, DECT phones etc. Probably the dominant signal around here is my phone shouting at the top of its RF voice trying to find a base station 

Even so, I wonder how much energy it takes to i) run the sensing circuitry and ii) be able to transmit packets of data reliably at a useful rate? Or how it compares with other technologies e.g. like PV (for fixed sensors) or piezo (for wearables)?