Ask Lemmy
A Fediverse community for open-ended, thought provoking questions
Rules: (interactive)
1) Be nice and; have fun
Doxxing, trolling, sealioning, racism, and toxicity are not welcomed in AskLemmy. Remember what your mother said: if you can't say something nice, don't say anything at all. In addition, the site-wide Lemmy.world terms of service also apply here. Please familiarize yourself with them
2) All posts must end with a '?'
This is sort of like Jeopardy. Please phrase all post titles in the form of a proper question ending with ?
3) No spam
Please do not flood the community with nonsense. Actual suspected spammers will be banned on site. No astroturfing.
4) NSFW is okay, within reason
Just remember to tag posts with either a content warning or a [NSFW] tag. Overtly sexual posts are not allowed, please direct them to either !asklemmyafterdark@lemmy.world or !asklemmynsfw@lemmynsfw.com.
NSFW comments should be restricted to posts tagged [NSFW].
5) This is not a support community.
It is not a place for 'how do I?', type questions.
If you have any questions regarding the site itself or would like to report a community, please direct them to Lemmy.world Support or email info@lemmy.world. For other questions check our partnered communities list, or use the search function.
6) No US Politics.
Please don't post about current US Politics. If you need to do this, try !politicaldiscussion@lemmy.world or !askusa@discuss.online
Reminder: The terms of service apply here too.
Partnered Communities:
Logo design credit goes to: tubbadu
view the rest of the comments
Ah, no. Electromagnetic induction and electromagnetic radiation are related but different - induction doesn't produce radiation (radio) waves that would travel longer distances.
It is possible to power a device with radio waves - the most basic crystal radio just drives a speaker using the acquired radio signal. In 1945 the USSR "gifted" a concealed listening device (The Thing) to the US ambassador which worked this way - it was only "on" when an external radio was transmitting the correct frequency, making it very hard to detect. RFID tags also work the same - they don't require batteries because the chip is activated when the tag's antenna gets hit by the radio from the scanner.
This is only practical for very low-power devices, because transmitting high-power radio waves is dangerous.
It would likely be sufficient for things like smart wearables, though. Maybe even smart watches
Maybe, but then you run into difficulty with antenna size. An RFID chip uses a tiny antenna but it's only expected to work within a range of about 1cm. To make the listening device I linked above work with a radio source in another room required an antenna 23cm long.
I doubt you could ever transmit enough power to drive a display this way, at least not safely because the output from the transmitter would have to be orders of magnitude higher, and the circuitry on the receiving end would have to be bulkier as a consequence or risk overheating.