I remember in the early 1950's a theme and variation of this device was available in kit form for a battery free radio albeit a crystal set with a set of horrible "brown's headphones. Sold by Levinsons a hobby store in Sydney, Australia.
It consisted of 2 tuned circuits, one set to the strongest RF field from an AM radio station. The output was rectified through a bridge rectifier to provide DC to amplify the second variable tuner output to a set of phones. One of the earliest transistors was used as the amp. Not quite the same but a variation on the "free power" concept. Another variation available was a low powered transmitter for morse code - had a range of about 3 metres, not very useful when you could yell across the room...!!!

Nifty. I have seen one-way communication without power, such as a crystal radio, but never two-way communication without power before.

Transmit texts? Improbable. User input is impossible once the device is powered down, which defeats the entire purpose, though the location tagging might be useful.
Except that the range is only several feet.
I think the uses would most likely lend themselves to areas like non-smart item retrieval, google-glass style VR, sensors, and credit cards.

Hope that this doesn't create interference or noise in TV or Cellular signals. Great idea otherwise, would love to see this used for vehicles and license plate tags.

a long time ago, people lit up their garden lights from high powered AM transmitters in Germany - which was illegal there and then! nothing new under the sun (moon)

and we wonder why the insects and bee's are dying

As none of us live in deep caves completely devoid of light, whats wrong with a button sized solar panel on the device that can gather extra power from the ambient light in a living room. It would certainly provide more power then this.

science ninja: I don't wonder. It's Monsanto's chemicals.

Wow! This is very interesting! I wonder how much this cost. I see this as a very important tool most specially if there are emergency cases where our cell phone batteries are dead.

in the late 50's my brother had a aprox 3" red missile shaped radio the silver top was a antenna you pulled up to tune in the stations am i think, used ear buds, no volume control but loud enough and no batteries used in it at all ! it sure would be nice if that company was still around making that product with both am/fm. would be great for power outages storms and free energy radio !!!!!!!!!