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Comment on Wi-Fi Devices That Use Stray Radio Waves as Their Power Source

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Any device which modulates the surrounding radio waves has the possibility of causing radio interference, so it will need licensing and type approval. And something which generates wideband crud will never be approved.

This thing is not passive. It is receiving, modulating, and re-transmitting broadband signals.

The "rusty bolt" form of radio interference is one of the most common that interference investigators have to deal with.

Even a device which merely absorbs radio waves passively could be seen as causing a kind of radio interference, because wifi (and similar short range systems) make use of reflected waves to go around obstructions.

This is an irrelevant loophole in the current regulations, but if you imagine a scenario where everyone is trying to power their smart wallpaper, smart windows and smart clothes by absorbing radio waves, perhaps it would be enough to reduce the reflected signal strength significantly.

No doubt true. Doesn't make it any less interesting as a cool hack though. If it's specifically trying to pick up "wifi" power in the 2.4/5GHz spectra that's obviously unregulated and approval is mostly a rubber stamp AIUI.

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