OMG, embarrassingly, actually v excited by this!

http://www.independent.co.uk/life-style/gadgets-and-tech/news/no-more-wires-a-home-has-successfully-been-powered-only-using-wifi-10293883.html

http://www.newscientist.com/article/dn27633-gadgets-powered-wirelessly-at-home-with-a-simple-wifi-router.html#.VW7Qvc9VhBc

In Seattle, six households have taken part in an experiment in which modified electrical devices were put in their homes along with a Wi-Fi router. Over 24 hours, the devices were powered solely by the router’s signal, which also continued to provide wireless internet access to the home.

How was this possible? The energy of the radio waves the router sent out was converted into direct current voltage with a component called a rectifier, much as solar panels convert light energy into electrical energy. That voltage was then boosted to a useful level by a DC-DC converter

It’ll give you something to aim for when you get more than 56k interwebnet speeds. 😀

That doesn’t exactly sound the most efficient way to charge things!

Also, Tesla.

Actually, speaking of tin-foil etc., I have a current client for whom I have to lay some more parquet in a few weeks. There are frickin’ ethernet cables appearing in and out of walls, screeds, floorboards being a right pain in the arse. The builders on site heard me cursing one of them while it was getting in my way a few weeks ago and both started laughing when I asked “what the **** are all these cables for?!?”. “Oh, she won’t have WiFi in the house mate. Thinks the radiation will kill the kids.” So, now the calpol conversation makes more sense. 😆

devices were powered solely by the router’s signal
…
That voltage was then boosted to a useful level by a DC-DC converter

Erm…

I’ve never heard of a DC-DC converter but took it to be the DC equivalent of a transformer.

Al: increased voltage by dropping current. “constant” power (W) excluding losses, I think…

I’ve never heard of a DC-DC converter but took it to be the DC equivalent of a transformer.

I suspect they mean something like a DC-DC Boost Converter:

[video]https://www.youtube.com/watch?v=wJU7AJgERG8[/video]

So a wi fi router can boil a kettle, run a TV, laptop, oven, shower, on 20W?

TBF the speed of the kettle boiling isn’t mentioned! (Probably 24hours as this was the length of the trial).

No mention of kettles in the New Scientist article. It does say:

The system powered temperature sensors and battery-less low-resolution cameras, and charged standard batteries.

and also

The Cota set-up can produce up to 20 watts, but would only deliver 1 watt to a single phone. CEO Hatem Zeine says that’s enough to charge an iPhone 5 several times over in a single day if it has constant access to the signal.

Sounds like an interesting application for this is Internet Of Things gadgets, which often don’t require very much power and need wifi anyway.

Tesla was trying to transmit power across long distances, IIRC.

Husband found dead, Wifi accused of murder.

Could the antenna be attuned to the mains frequency so that it picks up power simply from the fields around power cables in the house, rather than the specific WiFi signal?

Sounds like an interesting application for this is Internet Of Things gadgets, which often don’t require very much power and need wifi anyway.

Also useful for tablets, phones, smart watches, remote controls, wireless thermostats, smoke alarms, mini audio speakers, bike lights, bike GPS units?

Husband found dead, Wifi accused of murder.

😯

Seems likely to be extra-ordinarily inefficient to me.