UBT - Founder wrote:With so many sources of signals, (mobile phones, microwave links, wifi routers etc), it doesn't take a rocket scientist to figure out that with just a bit of circuitry, one could collect the radio frequencies and turn them into another form of energy...
It is very rare for broadcast radio signals to exceed 0.00025 mw/m2 inside a house, with VHF/UHF signals rarely exceeding 0.000007 mw/m2.
At a distance of 25 - 100m from a mobile phone base station, power levels of 0.1 mW/m2 - 3.0 mW/m2 may be expected.
So mobile 'phone signals will generally swamp any television/radio ones.
A 1 square metre RF antenna would collect 0.1 - 3 watts of power.
At the same efficiency as current solar panels, it would produce 0.012 - 0.51 watts of power.
(The experiment in the paper was performed at 16000 mW per square metre RF power :o )
UBT - Founder wrote:After all, isn't that what an AM radio does - turns RF into sound?
Your standard radio consumes much more power than it produces!
UBT - Founder wrote:So, what I want is a small device that collects said RF signals, plugs into a micro-usb port, so I can recharge my smartphone for free....!!!!
An iPhone battery produces ~ 5.5 watts. @ 70% efficiency charging, it needs 7.8 watts to fully charge. An S3 battery produces ~ 7.98 watts, 11.4 watts to charge.
Use solar power to charge your 'phone, use USB to charge your 'phone but harvesting power from thin air won't charge your 'phone unless you're sitting under a mobile 'phone mast with an umbrella sized antenna and have 15 - 950 hours to spare!
