Printable antennas suck electricity out of thin air11/09/2014 20:42
There's energy flowing around you all the time. And not in some spiritual, holistic sense: wireless energy from cellphone networks, routers, radios, TV transmitters, and even satellites is saturating the EM spectrum 24/7. If you're clever, you can tap in to some of this energy with printed antennas and use it to power battery-free electronics.
While there are a lot of different signals bouncing around out there in the ether, it's hard to extract a meaningful amount of energy from them, so despite this fantastical prototype wireless harvester from RCA that made a brief appearance at CES, it's unlikely that you're going to be charging any of your gadgets with this kind of tech.
What these power harvesters are good for is running networks of completely wireless sensors, since you can just stick them anywhere without having to worry about electrical connections, batteries, or even solar power. The few milliwats of electricity that they can generate consistently is easily enough to take temperature measurements, for example, and using capacitors they can even store up enough power for a brief wireless transmission to get the data back to you.
As far as making your life personally better, wireless sensor networks could be built into structures and vehicles to continuously check for any structural problems, or they could be deployed in airports to maybe allow the TSA to grope you slightly less, and that's something that we can all get behind.