Here's a video explaining WiFi backscatter. It really is an amazing concept even without doing HD video with it. All kinds of devices - I'm imaging home automation sensors - could become batteryless.

http://iotwifi.cs.washington.edu/

> All kinds of devices - I'm imaging home automation sensors - could become batteryless.

That's terrifying.

You can still use jammers to prevent backscatter from being readable but your jamming signal will just power the sensor more. :)

That is an amazing concept, simple and effective, just reflecting backscattered wifi signal on and off to encode data.

Thanks, that second paper is helpful. The OP is really the proof that passive Wifi is actually useful. In my opinion, the real advance here is in that second paper you cite, the fact that they've built Wifi enabled devices that are powered by the Wifi signal itself.