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Researchers discover battery-free technology which harvests power from radio and Wi-Fi signals for low-powered devices (www.tomshardware.com)

submitted 3 months ago by [email protected] to c/[email protected]

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cross-posted from: https://lemmy.ml/post/18426215

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[–] [email protected] 1 points 3 months ago (1 children)

Definitely not new. This is how RFID tags work. They harvest energy from the transmitter to power the circuitry in the tag to send back a response.

[–] [email protected] 1 points 3 months ago

And low-power really means low powered... Like... milliamps. If you fed an RFID chip directly, you'd need to supply about 1 mW depending on the specific chip... 1 milliwatt...

In order to feed that chip with a transmitter you feed up to 2W. So up to 99.95% losses... It's NOT economical for any other device that isn't super low power.

Hell Qi charging is just as bad. Qi2, newest and greatest... Which you basically have the devices touching only get up to 80% at absolute best efficiency numbers. Every mm you add, drops that number significantly.

None of this is going to enable "battery free" for basically anything that any consumer would care to be battery free. And honestly I wish we wouldn't pump the airwaves with all sorts of garbage just because it enabled the most minimal amount of "convenience" for things that never needed to be convenient to begin with.